Helluva Slayer

by GeneratedSmasher

When the young demon slayer, Tanjiro Kamado returns to the Butterfly Mansion after a mission, he ends up encountering a group of strange creatures who call themselves the "Immediate Murder Professionals". They are demons from Hell who are out to kill Tanjiro after a demon that he previously killed hired them. How will Tanjiro react to this situation? Well, things sure would happen!

AUTHOR'S NOTE: I've seen a lot of Helluva Boss crossover fanfics on the internet, but the one series that I'm surprised that no one has done a crossover fic with Helluva yet is the anime, Demon Slayer: Kimetsu No Yaiba, considering that the series revolves around demon hunters, and I thought that there could be many great stories if the two worlds ended up clashing together.So, since Helluva Boss AND Demon Slayer are two of my all-time favorite animated shows, I decided to step up to the plate and bring you my new fanfic, Helluva Slayer! A story where Tanjiro comes across I.M.P as they were out to kill him after getting hired by a demon that Tanjiro had previously slain, and many exciting adventures end up happening in the process!

I hope you all enjoy this exciting crossover!

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Out in the dark streets of Japan were a group of strange people wearing mysterious uniforms and swords around their waists. They were roaming the streets to find the scene of the mysterious murder of some civilians that happened earlier today.

This group of people were part of an organization known as the Demon Slayer Corps. A mysterious organization that is completely unidentified by the Japanese government. Their job is to hunt down man-eating demons who roam Japan's streets at night, and these mysterious murders have been happening for the past few months. Could it be that a demon is linked to these murders?

Nevertheless, they arrived at the scene where the murder took place and found four young adults lying dead on the floor and covered in blood. "What happened here?" Asked one of the slayers.

One woman who was wearing a haori that had the pattern of butterfly wings, black hair with purple streaks and a butterfly hairpin went to investigate the corpses. She examined them closely. "Hmmm…" She said. "It appears that the wounds these two have must've been from fire arm."

She pointed out a bullet hole on the foreheads of the victims. "Hey, Lady Kocho!" Another slayer said as he walked up and saw one of their limbs cut off. "I think some of their limbs have been severed from their body as well!"

Kocho examined the severed arms and legs as well as one of the victim's stomach sliced open. "Hmmm, it appears so." She said. "Maybe it could've been from some sort of sharp weapon. An axe perhaps?"

All the other slayers began shaking in fear. "Oh dear oh dear oh dear!" One of them said. "What kind of horrible monster would do such a thing? Could a demon have done this?"

"There's no doubt." Kocho said. "These murders have been going on for months now. But what kind of demon would do something like this?"

Watching them from a distance were three mysterious shadows. One medium-height sized one and two short ones. A mysterious portal opened up and the three unidentified entities hurried into the portal.

Kocho turned her head and saw something disappear into nothing. "Huh? I could've sworn I saw something…" She said curiously.

THE NEXT DAY…

Somewhere else in Japan lies a large manor that was filled with many different butterflies and a large cherry blossom tree in the garden. This is known as the Butterfly Mansion, a place for demon slayers to rest and for their wounds to be treated after being severely injured by demons in battle.

Although, the residents here are not demon slayers themselves, but girls who also offer training regiments to other slayers to strengthen them up. But there are three demon slayers who do reside here to train and get stronger.

First, there was Inosuke Hashibira. A hotheaded wild man who wears a boar mask on top of his head. Underneath though, he actually has a beautiful feminine face. He also thinks he's the strongest and claims to be the "God of the Mountains".

Next, there's Zenitsu Agatsuma. A cowardly young man with yellow hair. He's known for being quite scared at times and tends to run away from any situation he gets in just in case he might die. He also has a strong interest in women and hopes to one day get married before he inevitably dies. However, as wimpey as he might be, there's actually another side to him where if he falls asleep, he will sleep walk and start acting serious, no longer being afraid and determined to protect those around him.

Finally, there's Tanjiro Kamado. A kindhearted young boy with a scar on his forehead and an excellent sense of smell.

Before he joined the Demon Slayer Corps, he used to live in the mountains as a charcoal seller along with his family. But one day, his family was killed by none other than the great demon king, Muzan Kibutsuji, while his little sister Nezuko Kamado was transformed into a demon. Ever since that day, Tanjiro became a demon slayer and has sworn to defeat Muzan and turn his sister back into a human.

When other demon slayers first heard about a demon slayer traveling with a demon, they were shocked and thought it was against the corps rules. However, after some of them learned that Nezuko would never attack humans, thanks to a spell put on her by Tanjiro's master, Sankoji Urokodaki, they slowly started to warm up to her, as well as seeing Nezuko in action with her protecting humans. However, if Nezuko were to ever attack a human, she would immediately be executed and Tanjiro, as well as Urokodaki would commit seppuku.

These four have stuck with each other for a while now and have gone on many missions together. After their missions, they return to the Butterfly Mansion to heal their wounds and train for more tougher missions where they take on much stronger demons.

As such, Tanjiro Kamado was currently resting in his bed while focusing on his total concentration breathing. Total concentration breathing is a technique that Demon Slayers use to increase their lungs in order to take in as much air in order to increase their physical strength, speed and stamina. Tanjiro was also working on his Total Concentration Constant, which essentially means to constantly stay in the state for a long period of time to get stronger. He was resting in his bed working on it when suddenly…

"NOOOOOOOOOOOOOO!" Tanjiro suddenly woke up as he saw Zenitsu being dragged out of the room, as he was set to go out on another mission.

"I DON'T WANNA GO OUT ON ANOTHER MISSION!" He exclaimed while tugging on the door. "I DON'T WANNA GET EATEN BY DEMONS YET! I STILL HAVEN'T GOTTEN MARRIED TO NEZUKO YET, I CAN'T DIE BEFORE THAT, SO PLEASE DON'T MAKE ME GO!"

"Come on Zenitsu!" Said Aoi, one of the residents at the Butterfly Mansion. "It's for the good of the corps!"

Tanjiro just smiled at the sight and chuckled. "Oh Zenitsu," He said. "You never change."

Zenitsu saw that Tanjiro was now awake. "Tanjiro? You're awake" He said. Then he immediately broke free from Aoi's hold and rushed over to Tanjiro grabbing him by the head. "OH PLEASE TANJIRO!" He said while shaking him. "PLEASE DON'T LET THEM MAKE ME GO OUT ON ANOTHER MISSION! I DON'T WANNA FACE ANYMORE SCARY DEMONS! CAN'T YOU TAKE MY PLACE IN THIS MISSION FOR ME?"

Zenitsu stopped shaking Tanjiros head leaving him dizzy. "I-I'm sorry Zenitsu, but I have to train with Inosuke today!"

"He's right." Said Aoi. "Plus, this mission was assigned specifically to you. A Demon Slayer can't back down from a mission."

Zenitsu began shaking in fear again "B-b-but! I don't wanna!"

Tanjiro gave Zenitsu a sympathetic smile. "I do understand that you don't want to go, but you are a vital part of helping others from demons, and we are counting on you to do your best." He said with confidence. "Plus, we're all wishing you to return safely."

Zenitsu looked at him for a moment and then gave a sigh of defeat. "Fine… I'll go." He said sadly, in which Tanjiro gave him another smile. "That's the spirit, Zenitsu!" He said with confidence.

"But if I don't make it back alive, please tell Nezuko that I have always loved her!" Zenitsu then began to leave for his next mission, with his kasugai sparrow following Him.

"We're all counting on you." Said Aoi. "Be safe out there." This caused Zenitsu to blush. "Oh! U-uh, thank you Ms. Aoi! I'll come back safely! I'm sure of it!" Zenitsu then proceeded to leave the Butterfly Mansion for his new mission. Tanjiro gave a look of hope as Zenitsu left.

"GONPACHIRO!" Said a loud gruff voice. It was Inosuke, and he was all hyped up and ready to train. Inosuke usually tends to get other people's names incorrect. "I see you're awake now! Are you ready to train? I'm going to try everything I can to surpass you and become the strongest!"

Tanjiro chuckled a little bit. "Oh, right, I'm ready whenever you are Inosuke!" Inosuke let out a loud laugh. "Don't think because you're so confident you're going to become the strongest!" Inosuke said with a smirk underneath his boar mask. "I'm the God of the Mountains! And I will become stronger than you will ever be!"

"Then let's give it our all and train all day!" Tanjiro exclaimed. The two then began their training.

Their training mostly consisted of 300 push-ups, sit-ups, running through the mountains, sometimes while also carrying weighted objects, practicing their swordsman skills and even improving their breathing styles. Breathing styles are the main fighting styles that demon slayers usele that demon slayers use. Each style is based on a different sword fighting style that different demon slayers use. For example, Tanjiro's breathing style is Water Breathing, a style where its user will bend their body and weapon in a motion that matches the fluid motions of water. However, during his battle with a very powerful demon, he then learned an even greater technique known as the "Hinokami Kagura" or "Dance of the Fire God". Long ago during Tanjiro's early youth, in cold weather, Tanjiro's father would perform a dance that would keep his family warm. Years later, on a night when Tanjiro was battling one of the 12 powerful demon moons, he used the dance to defeat the Lower Rank 5 demon. Tanjiro hasn't been able to master the dance yet, as whenever he uses it, his stamina drops significantly and his body becomes very hot, as shown in his current training with Inosuke.

"Hinokami Kagura!" Tanjiro shouted as he swung his sword around while flame effects emerged from his sword. "Raging Su- AGH!" Tanjiro quickly stopped swinging his sword and immediately fell to the ground while hyperventilating.

Inosuke saw this and quickly rushed to his aid. "Kentaro!" He shouted. "Are you okay? Do you need food! I'll challenge you to an eating contest and I know I'll win first!"

Tanjiro regained his composure and got up while crouching down and took another deep breath. "I think I'm okay, Inosuke." He said. "I think I need to…take some rest before I continue." He then fainted to the ground.

After a while, Tanjiro was seen resting in his bed recovering from using the Hinokami Kagura. He then awoke and was greeted with three young girls by his side, checking to make sure that he was okay. It was three of the Butterfly Mansion's residents. Sumi, Kiyo and Naho. "Mr. Tanjiro!" Naho said. "You're awake! Are you okay?"

Tanjiro turned to them and sighed. "Yeah, I think I'm fine."

"Oh, it happened again Mr. Tanjiro!" Said Kiyo. "Your body temperature went up to 100 degrees again!"

"We should tell Ms. Shinobu!" Sumi exclaimed. "She should know something about this!"

This made Tanjiro worried. "No wait! Please don't!" He exclaimed. "Look, I'm fine now. I know that trying to master the Hinokami Kagura has taken multiple tolls on my body, but I know that I have gotten better with each time I use it! So please don't tell Ms Shinobu yet! Just a little while longer?"

The three girls looked at him with concerned looks on their faces and eventually, the three of them sighed in defeat. "Oh alright Mr. Tanjiro." said Sumi. "But you have to make sure to control your body temperature so this doesn't happen again!"

Tanjiro gave them a small smile. "I promise I will. Don't worry."

"In the meantime," said Naho, "We have cooked you some tasty snacks for you to eat to get you refreshed for more training! They're waiting for you in the dining area!"

Tanjiro's eyes lit upon hearing that. "Really? That sounds great!" He said in delight. "I'll head over there right now!" He then got up from his bed and made his way to the dining area.

On his way over there, he ended up seeing a familiar face. It was Shinobu Kocho, the Insect Hashira, and one of the 9 strongest swordsmen in the Demon Slayer Corps. She spotted Tanjiro and smiled. "Oh, hello there Tanjiro! It's great to see you!"

Tanjiro bowed down to her and greeted her back. "It's good to see you too, Ms. Shinobu!" He said.

"I take it your training has been going well so far?" She asked.

Tanjiro didn't want to tell her about her body temperature problems from using the Fire God Dance, so instead, he told her with confidence that training has been going quite well. "Yes." He said. "Ever since the passing of Mr. Rengoku, we have been training as hard as we can to get even stronger than ever before."

This made Shinobu chuckle. "That's great to hear!" She said. "Although, it's still a shame that we have lost him."

Tanjiro sighed sadly. "Yes. He truly was an amazing Hashira. I promise I will live up to his expectations." Tanjiro let out another sigh of sadness and then turned to Shinobu "If you don't mind me asking," Said Tanjiro "How have things been going with you?"

Shinobu then thought back to her previous mission from last night. "Well…" She began, "Me and the other Hashira have been investigating some mysterious murders that have been happening for months now."

This got Tanjiro intrigued. "Mysterious murders?" He asked. "Can you tell me more information?"

Shinobu then began to explain. "Almost every night, for three past few months, civilians have mysteriously been perishing. When we examine their wounds, they always look like they've been killed by some sort of firearm, or have their limbs severed off their body by some sort of sharp weapon, like an axe."

Tanjiro was shocked to hear about this. "Firearms and severed limbs? That sounds awful."

"It truly is." Said Shinobu. "And on rare occasions, it looks as though the victims were attacked by some sort of canine."

Tanjiro could not believe what he was hearing. What kind of horrible monster would do such a thing? And what would they be trying to achieve from doing something like this? "Could it be that a demon is behind something like this?" Asked Tanjiro.

"There's no doubt about it." Said Shinobu. "Though, we still haven't been able to get a glimpse of the demon that has been behind these murders. Not even a Hashira like myself has caught sight of them."

Tanjiro was surprised to hear this. Not even a Hashira has managed to catch even a glimpse of them? "I see." Tanjiro said. "I'm sure we'll be able to catch them soon. We can't let these murders keep going on. These are innocent people that they are hurting!"

Shinobu agreed with what Tanjiro said. "Yes. We need to work hard in order to catch these demons." She said with confidence. "By the way, haven't the girls told you that they have prepared a nice meal for you? You better hurry before it gets cold!"

Tanjiro then remembered. "Oh! Right! Thanks for reminding me. I'll head over there right now." He then got up and began to make his way to the dining area. "Thank you for the talk Ms. Shinobu."

"Anytime Tanjiro!" Said Shinobu with a smile.

In the dining area, Tanjiro and Inosuke were chowing down on their meal. Inosuke was going crazy with his dish and was stuffing his face with so much food very quickly, causing food scraps to spray everywhere. Meanwhile, Tanjiro was just sitting there, thinking about what Shinobu had told him about the mysterious murders that have been happening. Who is the demon behind these awful events, and what is their motivation for doing something like this. These thoughts clouded Tanjiro's mind as he just sat there, barely touching his food.

Inosuke noticed Tanjiro hasn't eaten anything yet and was lost in thought so he turned to him. "Hey! Kentaro!" He shouted. "You barely touched any of your food yet! You not hungry? Care if I have your food?"

Tanjiro then woke up and turned to him. "Oh! My apologies, Inosuke. I was just lost in thought." He said as he began to take a bite out of his meal.

Inosuke then became intrigued. "Really?" He asked. "What's this all about? Lay it on me!"

"Well, you see…" Tanjiro then began explaining to Inosuke what Shinobu had told him about the mysterious murders that have been happening for a while now, as he was explaining, Inosuke started to become more and more intrigued. "And that's what's been on my mind." Tanjiro said as he finished explaining.

"So, what I'm catching is… people have been mysteriously dying for the past few months, and the demon behind what has been happening hasn't been caught yet?" Inosuke asked, looking intrigued.

"Exactly." Said Tanjiro. "And not even a Hashira has managed to catch sight of this demon. I do hope we will catch them soon."

Inosuke stared at Tanjiro and then a look of self esteem appeared on his face. "Well, whatever this demon is, they will be no match for me! Inosuke Hashibira! God of the mountains!"

Tanjiro smiled at Inosuke's enthusiasm but tried to calm him down. "We shouldn't really get too confident about this Inosuke." He said. "What if this demon happens to be as strong as a 12 Kizuki demon?"

"Oh what are the chances of that happening Monjiro?" Inosuke said. "Besides, even if it were, I would still come out on top! The God of the Mountains has NEVER been defeated!"

"I wouldn't be so sure about that." Said Tanjiro with a contempt look on his face. "Remember what happened at Mt. Natagumo?"

Inosuke let out a growl of annoyance. "Don't remind me of that. I may have been defeated one time, but I promised myself that will never happen again!"

Tanjiro once again smiled at Inosuke's enthusiasm. "That's great to hear!" He exclaimed.

"SHUT UP!" Shouted Inosuke. "Anyways, 12 Kizuki or not, this demon who has been killing everyone recently will be no match for me!"

"Well then, we better start eating then so we can head back to training so we can get stronger" Tanjiro chuckled.

Inosuke then saw this as an opportunity to challenge Tanjiro to an eating contest. "Hmph, well then… I bet you won't be able to finish before me!" Inosuke said as he began shoving a handful of food into his mouth.

Tanjiro then laughed. "Oh it is so on!" He then began eating his food quickly, determined to beat Inosuke in this eating contest.

After they had finished eating, they resumed their training session which lasted for the rest of the day. However, as they trained, Tanjiro still couldn't get his mind off of the mysterious murders that were happening. Because of this, his training started to become a little bit rusty, but he didn't want to make Inosuke and the other residents at the mansion worried about him, so he tried hard to stay focused and still manage to get it done. He did hope that one day he would capture the demon who was causing these murders, but what he was the most curious about was what this demon is like and what their motivations are. Still, he and Inosuke trained for the rest of the day.

After a long day of training, Tanjiro and Inosuke were resting in their beds. Just then, the three butterfly girls went up to Tanjiro's bed to check up on him. "Mr. Tanjiro!" Said Sumi. "Has your body temperature gone down?"

Tanjiro sat up in bed and nodded. "Yes. I do believe I'm feeling better." He said. "I know I can master the Hinokami Kagura, but I just don't think my body is ready for it yet… Maybe I should probably stick to water breathing for now."

"That's probably a good idea." Said Kiyo.

"If this keeps happening you could die from your body getting too hot!" Naho exclaimed.

"I know, I know." Said Tanjiro. "But I do believe that as I get stronger, my body will be able to handle it. Thank you for checking up on me girls."

The three girls nodded and Tanjiro layed back down into bed. But then, the three girls noticed Tanjiro was thinking about something and became concerned. "Um, Mr. Tanjiro?" Asked Kiyo. "There must be something on your mind. Are you feeling okay?"

"Hm? Oh, I-I'm fine. I just had a long day of training." Tanjiro said, trying to put the thoughts of the mysterious murders behind him.

The three girls were still concerned for him, but they decided to just let him rest for the night, as there would be a lot more training for the days to come. The three girls then proceeded to exit the room, and Tanjiro closed his eyes, and began to fall asleep.

MEANWHILE…

Somewhere out in a dark alleyway, a man was seen running away from something and had a panicked look on his face. He gasped when he saw a dead end and accidentally tripped over a curb causing him to fall over and hit the dead end. He turned around and saw what was chasing him, a mysterious horned shadow that was slowly approaching him.

"P-please! Don't hurt me!" The man begged. "I-I have a daughter I need to feed at home, and she's worried about me!"

The figure didn't listen and pulled out some sort of flintlock and aimed it at the man.

"NOOOOO! PLEEEEASE!" The man screamed. "SPARE MEEEEEE!"

BANG!

The man fell limp on the ground as the unknown entity fired its flintlock at the man's forehead, killing him instantly. Then, a mysterious portal appeared out of nowhere and the creatures stepped through it followed by two other smaller creatures, and then the portal closed. Just then, another Demon Slayer arrived on the scene and saw the man lying dead on the ground.

"Damn it!" The slayer exclaimed. "It's happening again…" Just then, three other Demon Slayers arrived on the scene as well as another one who stood out from the others.

He had white spikey hair, a white haori that exposed his bare chest, some scars on his body and face and a pair of bloodshot eyes. He walked up to the man's lying corpse and growled to himself. "Whatever demon is behind all this, I will KILL them with no mercy!" He exclaimed.

THE NEXT MORNING…

Morning rose back at the Butterfly Mansion. Tanjiro and Inosuke were seen sleeping peacefully in their beds. But they wouldn't be sleeping for long as they were suddenly awoken by a loud sound of a door slamming open. Tanjiro got up and saw Zenitsu standing in the doorway with a traumatized look on his face. Tanjiro was happy to see him since he had successfully returned from his mission.

"Welcome back Zenitsu!" Tanjiro said happily. "How was your mission?"

Just hearing this made Zenitsu's eye twitch. "How was my mission…?" He asked dumbfoundedly and suddenly gave a look of shock "HOW WAS MY MISSION?!?!?!?!?!?!??!?!" He then rushed up to Tanjiro and began poking him hard in the face. "IT WAS ABSOLUTELY AWFUL I TELL YOU!!!!!!!!!!!!!!" And then he proceeded to have a big meltdown.

"I CONSTANTLY KEPT GETTING YELLED AT BY THE OTHER SLAYERS FOR NOT FOLLOWING DIRECTIONS!!!!!!!!!!!!! NOT TO MENTION THE DEMON I HAD TO FACE WAS SO STRONG AND TERRIFYING!!!!!!!!!!!!! I ALMOST LOST MY ENTIRE ARM DURING MY FIGHT WITH HIM!!!!!!!!!!!! I THOUGHT IT WOULD HAVE BEEN THE END FOR ME AND I NEVER EVEN GOT TO GO ON MY FIRST DATE WITH NEZUKOOOOOOOOOOO!!!!!!!!!" Zenitsu began to sob into Tanjiro's chest. Tanjiro pulled Zenitsu off of his chest, leaving a trail of snot from Zenitsu's nose onto Tanjiro's shirt.

"Well I am happy that you managed to survive!" Tanjiro smiled. "After all, you're a vital aspect of our team! We wouldn't have won most of our battles with other demons without your help!"

Zenitsu gave Tanjiro a gloomy glare. "Don't think that your sympathy is going to make me feel better…"

"HA!" Inosuke exclaimed. "You're just being a big baby as usual! A guy like me would've slain that demon very easily!"

"SHUT UP ALREADY YOU STUPID BOAR!" Zenitsu yelled.

"WHAT DID YOU JUST CALL ME JUST NOW?!" Inosuke shouted.

Tanjiro sighed as he saw the two began to have their usual arguments. Soon enough, the three of them began to have their meals and began their usual training sessions.

First, the trio started with 600 push-ups. It didn't seem so bad, until you realize that they had to do it with three of the butterfly girls sitting on their backs while they were doing it, providing an extra challenge as they had to deal with the weight on their backs.

Next, they had to run miles through the mountains. Sometimes they did this while carrying heavy weights. Almost every time, Inosuke would be in the lead. "Hahahaha! The god of the mountains never falters on a task like this!" He exclaimed with energy.

After that, they began to have some spars with each other, while also improving on their breathing styles. Inosuke practiced on his Beast Breathing, while Zenitsu worked on his breathing technique, which was Thunder Breathing. However, Zenitsu only knew the first form of the technique, he does utilize different extensions of the form. Tanjiro meanwhile wanted to practice his Hinokami Kagura technique, but he was worried he would pass out again from his body getting too hot after using one of the forms. So instead, he decided to practice on his Water Breathing.

The next training exercise they did was one that they would do to improve their total concentration breathing, and that was blowing into a giant water gourd until it breaks. As they were blowing, the three butterfly girls cheered them on. "Come on!" "You got this!" "Give it your all!" And soon enough, all three of their gourds cracked open and the three girls cheered for them. "Yay!" "We knew you could do it!" "Way to go!"

They did other training exercises as well, which mostly consisted of improving their strength. They lifted heavy weights, did some sit-ups, broke some solid bricks with their bare hands, and many more. Their training lasted all throughout the week.

One day, when the three of them were having a meal after a long training session, Tanjiro was still thinking about the murders that have been happening. As Zenitsu was eating, he noticed that Tanjiro had his head in the clouds and became concerned.

"Huh? Hey Tanjiro," Zenitsu said, trying to get his attention. "Are you okay? You haven't really spoken all day."

Tanjiro woke up and noticed Zenitsu talking to him. "O-oh, I'm doing fine Zenitsu." He replied. "It's just…something has been on my mind lately that has left me worried."

Zenitsu became more concerned from hearing this. "What?! What's going on?" He asked.

"Heh, he's probably thinking about how people have been mysteriously dying for the past few days." Inosuke said with a smirk.

"Wait, what?!" Zenitsu exclaimed. "People have been mysteriously dying?!?!?!? That sounds horrible! What do you know about this Tanjiro?!" He grabbed onto Tanjiro's shirt begging him to explain what was happening.

"Well, you see…" Tanjiro began to explain to Zenitsu about the mysterious murders that have been happening, and as well as how nobody has managed to catch a glimpse of the demon who was behind these murders. "And that's basically what's going on." Tanjiro finished explaining.

"And not even any of the Hashira has managed to catch sight of this demon yet?" Asked Zenitsu, looking shocked after hearing Tanjiro's story.

"Unfortunately not." Said Tanjiro.

"That sounds horrible!" Zenitsu exclaimed looking quite scared. "Oh I hope I don't come across this demon soon… I already had many near death experiences in my last encounters with other demons, so if I run into this one, I'LL BE DONE FOR!"

Inosuke just laughed from hearing Zenitsu's reaction. "Ha! Well if I ever ran into that demon, they would be running for their lives once they lay eyes on me!" He exclaimed with confidence.

Zenitsu gave an annoyed look. "Could your ego be any higher?"

"Hey, shut up!" Inosuke growled. "I know I can take on whatever demon is causing all these murders!"

Tanjiro chuckled nervously at the two. "Alright, settle down you two." He said calmly. "We shouldn't really get too excited over this demon. In fact, I don't think we're fully prepared to take it on."

The two sat there for a moment processing Tanjiro's words. "You're right Kentaro." Said Inosuke. "Which is why we need to finish our meals quickly so we can train as hard as we can so we will be able to take the demon on!" Inosuke then began to shove food into his mouth getting scraps everywhere as he chewed and some of it got on Zenitsu's face.

"Can you slow down?!" Zenitsu yelled, but then turned to Tanjiro. "But, I think you're right Tanjiro." He said calmly. "I also don't think we're strong enough to take this demon on. And I just hope-" He was cut off by Inosuke's loud eating. "And I just hope that when we-" He tried to speak but Inosuke's loud eating and the scraps flying into his face kept interrupting him. "WILL YOU STOP EATING FOR A MINUTE?!" He yelled at Inosuke. "I'M TRYING TO SPEAK HERE!"

"DON'T TELL ME WHAT TO DO!" Inosuke shouted back. "I WILL EAT WHENEVER I WANT!"

"Alright alright, break it up you two." Tanjiro intervened, and the two stopped fighting. "Now, Inosuke, please let Zenitsu finish."

"Hmph." Inosuke pouted and Zenitsu continued to speak.

"Now, as I was saying, I hope that when we DO have to take on the demon, it won't be just one of us taking it on. Especially not me! I don't know what I would do if I had to take on a big scary demon without you to back me up Tanjiro!"

Tanjiro looked at his friend and put a hand on his shoulder. "Don't worry Zenitsu. I'm sure that when the time comes that when we do have to face this demon, we will do our best and defeat it."

Zenitsu sighed as he knew he had to fight said demon one day. He nodded in defeat and agreed with Tanjiro. "Alright Tanjiro. But if I don't come out alive when I do face it, can you please tell Nezuko-" He was then rudely interrupted by Inosuke's loud eating again. "CAN YOU STOP EATING LOUDLY WHEN I'M TRYING TO TALK, DAMMIT?!"

"Huh?" Tanjiro said confused. "You want me to tell Nezuko to stop eating when you talk?"

"NO I WANT TALKING TO…" Zenitsu let out a loud groan which Tanjiro chuckled to.

"Anyways, I think we should continue our meals so we can get back to training. We need to be fully prepared if we ever have to face whatever demon is behind the murders." Tanjiro said as he began to dine into his food.

LATER THAT NIGHT…

Out in a dark alleyway of a village, a group of people were backed up against the wall and shaking in fear.

Just then, two men got shot in the head, killing them instantly. Another man tried to flee the scene but unfortunately, he was shot too, causing him to fall onto the ground and go limp. One woman who was on her knees praying to not be killed ended up getting her head sliced off by some sort of axe, causing her body to fall onto the ground and her head rolling across the ground leaving a trail of blood in the process.

After the massacre was over, the corpses of the group of people laid on the ground, cold and bleeding. Just then, a mysterious figure began to slowly walk up to the scene in the shadows. It was tall, and it looked like it had some sort of horns coming out from its head. The figure then began to emerge from the shadows revealing itself.

It was a tall male humanoid creature with sand colored skin, a black mullet with dark green streaks at the end, a pair of huge horns coming out from his forehead, had some sort of cracks along his face, and was wearing a large burgundy cloak that covered its entire body. This creature was a demon. A creature that roams Japan's streets at night and feeds only on human flesh. The demon slayer corps hunts down monsters like him to protect humanity from them, but since there didn't seem to be any demon slayers around, this was his perfect chance to feast on any humans without worrying.

The demon looked at the aftermath of the massacre, and an evil grin appeared on his face. "Hmmm, fresh meat just out in the open?" He asked in amusement. "Don't mind if I do." He then slowly walked up to one of the dead humans and crouched down to him. And then, he began to feast on him, devouring the human's flesh and licking the blood off his fingers.

Little did the demon know that he was being watched. What was spying on him was some sort of crow who was sitting on one of the tall structures of the village. This crow was a kasugai crow. They are the messengers of the demon slayers to inform them of any demons that have been spotted near civilization. When it saw the demon feasting on the dead humans, he began to fly off.

"CAWWW! DEMON SPOTTED!" It exclaimed. "DEMON SPOTTED IN A NEARBY VILLAGE!"

BACK AT THE BUTTERFLY MANSION…

The morning was approaching, and Tanjiro, Zenitsu and Inosuke were all resting in their beds after yesterday's training.

Zenitsu slowly began to open his eyes. He then turned to Tanjiro who was asleep. "Hey Tanjiro?" He asked.

Once Tanjiro heard Zenitsu's voice, he slowly awoke. "Hmm? What is it, Zenitsu?"

"I'm starting to get worried about the demon you told me about. You don't think I will have to be the one to fight it, right?"

Tanjiro saw that his friend was worried, so he gave him a sympathetic smile. "Zenitsu," He began. "You don't have anything to worry about. What's more concerning to me is when we'll catch this demon. It hasn't been sighted by any other demon slayers, not even any of the Hashira, so who's to say that we won't be running into it anytime soon?"

"Well that's the thing Tanjiro!" Said Zenitsu. "If we do catch it they will most likely choose me to take it on! And I'm sure that I won't even survive it! I can't die before I go on my first date with Nezuko!"

"Hey hey hey, listen to me Zenitsu." Said Tanjiro. "Everything is going to be fine. It doesn't matter who they choose to take the demon on, what matters is defeating the demon so these murders won't be happening anymore. And even if they choose one of us, I do know we will be able to defeat it." Tanjiro looked at Zenitsu with a reassured smile.

Zenitsu looked back at him and lowered his head in sadness. "I just don't know Tanjiro." Said Zenitsu. "Do you really think someone as weak and useless like me will be able to take the demon on?"

"Oh Zenitsu," Tanjiro said. "You're not useless. You're a vital part of our team. And like I said before, we wouldn't have won many of our missions without your help."

Zenitsu looked at him for a moment and then glared at him. "I told you before, sympathy isn't going to make me feel better! And besides, even if I was useful, I wouldn't be able to hold them off for too long…"

"Well," said Tanjiro "We'll just have to see when we do eventually have to go up against this demon. Now, let's continue to rest. We wouldn't want to be sleepy when we train today, wouldn't we?" Tanjiro then proceeded to return to his sleep, and Zenitsu stared at him and sighed.

"Tanjiro and his positive attitude." He sighed. "Well, he always knows how to make us feel confident." He then returned to his sleep. But just then…

"SQUAK! DEMON SPOTTED!" Tanjiro, Zenitsu and Inosuke all shot awake. The kasugai crow arrived to inform them of a new mission. "DEMON SPOTTED IN A NEARBY VILLAGE! THIS DEMON IS SUSPECTED TO BE BEHIND THE MYSTERIOUS MASSACRES THAT HAVE BEEN HAPPENING!" Tanjiro gasped when hearing this. "TANJIRO KAMADO IS TO BE ASSIGNED TO DEAL WITH THIS DEMON!"

"Yes! Right away!" Tanjiro exclaimed as he got out of bed and began to prepare for his new mission.

Once Tanjiro was in his Demon Slayer Corps uniform, he tightened his nichirin sword around his waist, put on his green and black checkered haori, and put the wooden box that his little sister, Nezuko travels in on his back. Once he was ready, the three butterfly girls walked up to him.

"Here you go Tanjiro!" Said Sumi, handing him a box of rice balls.

"We wouldn't want you to get hungry during your mission!" said Kiyo.

"Thank you girls!" Said Tanjiro with a smile on his face. He took the rice ball and wrapped it in some paper, and then placed it into his pocket.

Tanjiro was then getting ready to leave the mansion and set out on his mission. Zenitsu, Inosuke and the three butterfly girls were waving goodbye wishing him a good luck.

"Stay safe out there Tanjiro!" Said Naho.

"We hope you will be able to defeat that demon!" Said Sumi.

"Oh I hope you don't die Tanjiro!" Said Zenitsu sounding worried. "If you die then I won't know who will protect me! Well, besides Nezuko of course…"

"Don't worry guys." Said Tanjiro. "I promise I will return safely. And the murders will finally be put to an end!"

"If you do come back alive Kentaro," said Inosuke, "tell me what that demon was like! I would like to know how powerful it was!"

Tanjiro chuckled. "Of course Inosuke." Tanjiro then turned around getting ready to set off. "Well, looks like I'm off now. Goodbye guys!" Tanjiro then set off for his mission.

"Goodbye Mr. Tanjiro!" Said Kiyo.

"DON'T DIE OUT THERE!" Shouted Zenitsu.

"GO GET THEM MONJIRO!" Exclaimed Inosuke.

"THE VILLAGE IS NORTH!" Shouted Tanjiro's kasugai crow. "THEN YOU WILL TAKE A FEW TURNS ALONG THE WAY!"

Tanjiro followed his kasugai crow to the village where the demon was spotted. He traveled through fields of grass and across the rivers. Sometime during his travels, he decided to have his riceball that the butterfly girls made for him, as he started to get hungry. The rice ball was stuffed with a plum filling and it was delicious and Tanjiro savored every bite of it. After he was finished with his onigiri, he continued his travels to the village.

Eventually, Tanjiro finally arrived at the village. "It looks like I have finally arrived." He said as he looked around the village and saw other villagers enjoying their normal lives. He saw some children playing catch with their parents and an elderly couple having a nice meal. The normal lives of these villagers couldn't help but make Tanjiro smile. He then turned to his box to check on his sister. "Nezuko, are you doing okay?" There was no response, as Nezuko was currently asleep, since sleeping is how she gains most of her strength rather than feasting on human flesh like other demons do. "Ah, right." Tanjiro. "Well, continue to get some good rest."

Tanjiro looked around the village some more. "Well, it's still day time, so it will be a while before the demon eventually comes out," he said. "Maybe I should go ask some of the villagers if they know anything about the mysterious murders." He then proceeded to enter the village and began to ask the villagers.

"Mysterious murders?" asked a cranky elderly man who Tanjiro was asking. "Have you been in the sun for too long, kid? There are no murders that happen in this village! Now get lost!"

Tanjiro then asked another villager, who was a young man who looked to be in his 20s. "I haven't seen many murders happening in this village." Said the man. "However, I do recall my sister saying her fiance was mysteriously shot and killed. But I don't know the reasoning for it."

"Do you recall what her fiance did before he mysteriously died?" Asked Tanjiro.

"You shouldn't involve yourself with this stuff, kid." Said the man. "That's my sister's business and not yours." And then he walked off, leaving Tanjiro a little disappointed.

The next person he talked to was a young woman who was drinking some tea. "Oh dear, I have heard rumors going around all of Japan that people have been mysteriously dying every night! But I haven't heard anything about anything happening in this village!"

Tanjiro continued to walk through the village to see if there are any other villagers who know anything about the murders when suddenly… He heard the sound of sniffing and sobbing. He turned and saw a little girl crying while some police officers were speaking to her.

"And are you sure that your parents didn't return last night?" asked one of the policemen.

"Y-yes." The little girl sniffed. "But this can't be! Mommy and daddy always arrive home on time! I just hope they…they didn't get…" The girl continued to sob while the police comforted her.

Just seeing the sight of a little girl losing her parents was enough to make Tanjiro sad. Could the demon be the one behind their disappearance? Tanjiro then started to become angry. "You bastard…" Tanjiro muttered. "Those people you killed were parents of an innocent little girl! And now she has no family to look after her! You demons really are heartless creatures… I swear I will find and defeat you, and avenge that girl's parents!"

After a while of gathering information about the demon, the sun was beginning to set. Tanjiro was sitting down gathering the information he got. While some of the villagers simply ignored him, and others were being rude to him, some of the villagers told him that they had heard rumors about murders. But the one thing that stood out to him the most was that little girl who lost her family, and just thinking about it continued to make Tanjiro angry. "I swear it…" Tanjiro though. "I will defeat you no matter what."

But then, Tanjiro started to get hungry. After all, he spent his whole day gathering information on the demon. "Oh dear." Tanjiro said. "I can't find the demon on an empty stomach. There should be some sort of food stand around here."

Tanjiro looked around to see if there were any food stands or restaurants nearby. Then, he spotted a small ramen shop near the bench he was sitting on. "Aha! A ramen shop!" Tanjiro said. "That ought to fill my stomach up."

Tanjiro got up and made his way to the ramen shop. There was a man working there as the shop owner and he smiled as he saw Tanjiro come in. "Ah, welcome! Come on in!" Said the shop owner. "May I get you anything?"

"Yes please." Said Tanjiro. "I would like a bowl of udon with added yam."

"Yes of course." The shop owner replied. "I'll bring it to you as quickly as I can." The man then began to prepare Tanjiro's udon and Tanjiro took a seat. As the man was preparing the udon, Tanjiro decided to ask him about the murders.

"Hey, I'm sorry to disturb you, but I have a question if you don't mind me asking." Said Tanjiro.

"I don't mind at all." Said the shop owner. "Go ahead, what's your question?"

Tanjiro took a deep breath and began to ask. "So, I've been hearing some rumors that there are some mysterious murders happening throughout the country, and I was wondering if you knew anything about them."

The shop owner looked surprised upon hearing this. "Mysterious murders huh?" He said. "Now that you mention it, I did hear a customer from earlier today saying that two of his friends went missing last night."

"I see." Said Tanjiro. "Was the customer a villager from this very village?"

"Yes he is." Said the shop owner. "I've seen him come into my shop once in a while. I do hope he's doing fine after the loss of his two friends."

Tanjiro looked down and sighed. "Me too…" He was more determined to take the demon down and put these murders to rest once and for all now. The shop owner was now done preparing the udon and placed it in front of Tanjiro.

"Here you are kind sir." He said. "One bowl of udon with added yam."

Tanjiro then put his hands together and closed his eyes. "Many thanks!" Tanjiro then took a pair of chopsticks and prepared to dine into his udon. After one bite of it and slurping the broth, he could say that it was quite delicious.

It was now dark out and Tanjiro was finished with his udon. "Thank you for the great meal sir!" he said.

"Anytime kid." Said the shop owner.

Just then, Tanjiro heard the sound of a shrieking woman.

"Huh? That sound!" Tanjiro thought. "It was the sound of a screaming woman! And…" Tanjiro sniffed the air and held his nose. "That scent! There's a demon nearby!" Tanjiro then quickly got up and began to run out of the shop to find where the shriek was coming from.

"Hey, where are you going, kid?" Asked the shop owner in surprise.

"Um, I have…important business to attend to, but thank you for the meal! Money's on the table!" Tanjiro said as he rushed out of the shop.

"Uh, anytime kid. Anytime." The shop owner said while looking rather confused.

Tanjiro quickly rushed to find the source of the demon. He ran past a crowd of villagers who were surprised as they saw the young boy run past them late at night. One of them even almost got bumped into by Tanjiro. "Hey! Watch where you're going, you punk!" The villager shouted. "M-my apologies!" Called Tanjiro.

Meanwhile, a woman wearing a pink kimono was slowly backing away with a knife in her hand. "S-stay back! I'm warning you!"

"Oh what's the matter little lady? Just stay calm and LET ME DEVOUR YOU!" The creature that was approaching her was the same large demon with the black mullet with green trims and long burgundy cloak that the kasugai crow spotted last night.

"I-I don't know who you are or what you want for me, but you better stay back before I either call the police or take action myself!"

Just then, the woman felt herself being violently grabbed by the demon's large meaty hand. "Shut up already you mouthy bitch!" Shouted the demon. "Let me make this nice and quick so I can move on to my next meal!"

The woman winced in fear as the demon gave her a scary grin getting ready to devour her.

"HEY!" Shouted as voice. The demon turned and saw Tanjiro standing there looking fierce. "You leave that poor woman alone!"

The demon just smiled in amusement and slowly approached Tanjiro while still holding the woman in his hand. "Well well well…what have we here?" The demon looked at Tanjiro with an evil grin on his face and then examined him. "I recognize that uniform." Said the demon. "You must be one of those demon slayers I've heard so much about!"

"That's right!" Said Tanjiro looking determined. "I also have a few questions for you!"

The demon scoffed. "I don't have time for any foolish questions." He retorted. "And it's also rude to interrupt someone during their meal!" He began to sink his nails through the woman's flesh.

"Don't hurt her!" Tanjiro shouted.

"Why should I not?" Asked the demon. "After all she was practically asking for me to eat her when she threatened me with that knife…"

"I-IT WAS AN ACT OF SELF DEFENSE!" Cried the woman.

"This is just sickening to watch." Tanjiro thought. "Well, I have a job to do, so I might as well ask him." He then stepped forward and pointed at the demon. "Are you the one responsible for the mysterious murders that have been happening?!"

The demon growled. "SO WHAT IF I AM?!" He shouted. "AND I HAVE NO RIGHT TO ANSWER ANY OF YOUR FUTILE QUESTIONS!"

"WELL WHAT DO YOU GAIN FROM DOING ANY OF THIS?!" Tanjiro shouted back. "THESE ARE INNOCENT HUMANS YOU ARE HURTING!"

"WHAT'S IT TO YOU, KID?!" The demon yelled. "I DO THIS BECAUSE HUMANS ARE WEAK FOOLISH CREATURES WHO SNOOP THEIR NOSE INTO OTHER DEMONS BUSINESS! I WAS JUST MINDING MY OWN BUSINESS FEASTING ON SOME DRUNK HOBO WHO WHO LOOKED AT ME FUNNY WHEN THIS OLD HAG HERE WAS SPYING ON ME! SO NOW I'M GOING TO TEACH HER A LESSON!" The demon didn't noticed that the woman was raising her knife at him. She then proceeded to stab him in the neck.

"ARRRRGH!" The demon yelled in pain. He turned to the woman with a scary looking glare on his face. "You just made a HUGE mistake, old hag!" He then grabbed the knife and yanked it out of his neck, tossing it to the ground. "Now it's time for me to have some fun…" He then proceeded to sink his sharp nails into the woman's chest with left hand and ran them down her front causing blood to spill out of her.

"NO! STOP! IT HURTS!" The woman screamed.

Tanjiro had to act quickly, or else this poor woman was done for. He then grabbed his sword and began to draw it, and then he took a deep breath. "Total concentration…" He whispered. "Water breathing…fourth form…" Then Tanjiro quickly dashed forward and slashed right through the demon's arms causing them to fall off his arms, releasing the woman. "STRIKING TIDE!"

The woman fell to the ground and the demon fell back as Tanjiro slashed his hands off. He then glared at Tanjiro giving him a growl.

Tanjiro then quickly rushed to the woman's aid. "Are you hurt ma'am?" He asked.

"I-I'm not sure." The woman said weakly. "It hurts really bad."

"Put some ice on that wound, it will help with the bleeding." Tanjiro said.

Just then, the two of them heard the demon snickering as he slowly approached Tanjiro. "You've got guts kid." He said, and he slowly began to regenerate his hands, as one of demons' main abilities is being able to regenerate any wounds they receive. "I see you really are looking for a fight with me. But it's gonna take a lot more than that to take me down!"

"Get back!" Tanjiro warned the woman. "This could get ugly, and I don't want you to get more hurt!"

The woman nodded "Uh, r-right!" She then slowly began to back away from the confrontation.

"Don't waste your time with her." The demon said. "She'll be dead before you will be able to even finish me off!"

"I will not allow that to happen!" Tanjiro exclaimed. "That woman WILL survive, I'm sure of it!"

"Tch, that woman is bleeding out of her chest." Retorted the demon. "She'll run out of blood in no time and there will be nothing you can do about it."

"She will be able treat her wounds soon! I'm sure of it!" Tanjiro said. "In the meantime, I will NOT let you hurt her any further! She is an innocent human, and I will defeat you no matter what!

The demon looked at him with an look of amusement. "Oh?" He said. "So you're pretty much asking for me to kill you then?" He then slid his hands underneath his cloak. "Hmph, very well then." Suddenly, he threw his cloak right off his body revealing his large muscular body and his extra pair of arms. "I'LL JUST BE SURE TO MAKE IT QUICK AND PAINFUL!"

Tanjiro was in shock as he saw the demon's extra arms. He thought that this was going to be more challenging than he thought. But what really got him in shock was what was in each of the demons hands. In his upper hands were two battle axes while in his lower arms were two guns. He then thought back to what Shinobu told him the other day.

"When we examine their wounds, they always look like they've been killed by some sort of firearm, or have their limbs severed off their body by some sort of sharp weapon, like an axe."

Tanjiro was now in a state of shock. The possibility of this demon being behind the murders just shot up. But he couldn't hold back. He had to defeat the demon as well as protect the woman. He then got into a battle stance and began to face the demon.

"Now, which one of us will strike first?" Asked the demon, as the two of them stood there, while the woman was slowly backing up against the wall. Tanjiro had to think as he stood there. He knew he had to strike, but he wasn't sure if he should go first, as he didn't know what this demon was capable of. The demon just stood there looking at him in amusement and waiting to see what his move will be.

"I don't think this demon is going to act unless I strike." Tanjiro thought. "I need to think of a plan." Tanjiro thought of his plan for a moment. "If he fires his bullets, I'll have to try and dodge them, but if he swings his axes, I will have to try and block them. I'll just have to see what his action will be." Tanjiro then gripped his sword and began to charge towards the demon.

The demon then snickered. "I knew this would be too easy." He then quickly fired his bullets from his two guns and swung his axes around.

Tanjiro was quickly caught off guard from his action. "Shoot!" he thought. "I didn't think he would do both at once! I'm going to have to quickly come up with a new plan!" Tanjiro quickly thought to himself as the bullets were approaching him. "I got it! I'll use my third form to block both the bullets and the axes! That should work!" Tanjiro got into position and began to use the third form of water breathing.

The demon laughed at him. "What's wrong kid? Are you scared because you have no options left?" He said tauntingly.

"Water breathing…third form…" Just then, Tanjiro's body began dancing in a flowing pattern and he managed to slice through the bullets and block the demon's axes. "FLOWING DANCE!" With enough force, Tanjiro snapped one of the demon's axes in two, and the demon fell back.

The demon was still smirking in amusement, clearly not taken back by Tanjiro's swordsmanship. "Not bad, not bad." He retorted. "But still not enough. However, I can tell that you are experienced enough to take me with just my normal weapons on."

Tanjiro became confused when hearing that. "Normal weapons? What could he mean by that?" He thought.

"Well then…" The demon said as he reached for his cloak and pulled out another battle axe. "Let's see if you're well experienced to take on my pets…"

Tanjiro gripped his sword tightly. "Pets? That can't sound good…" He thought.

The demon then raised his two axes. "Blood Demon Art…" He said and then…he swung his two axes into the ground with much force, cracking the ground beneath him. "STONE WOLVES!" Just then, two canine-like creatures emerged from the ground. They looked like they were sculpted stone statues and they both snarled at Tanjiro.

Now, Blood Demon Arts are special abilities that higher-leveled demons have. Each demon has a different type of art, being based on a central theme. In the case of this demon here, he can use his weapons to create powerful canines from the ground beneath him. "Go my lovely dogs! Kill this pathetic child for me!" The demon said as the wolves began to charge at Tanjiro.

"This demon can use Blood Demon Arts?" Tanjiro thought to himself. "This is not good… I'm going to have to fight off these two wolves before I can go back to fighting the main demon. But wait, wolves? Then that means…" He then had another flashback to what Shinobu said about the culprit of the murders.

"And on rare occasions, it looks as though the victims were attacked by some sort of canine."

It all started to add up now. "So this demon must've used his blood demon art on occasions to kill his victims. This is just sickening to think about!" Tanjiro gripped his sword and began to take on the wolves. One of the wolves began to pounce him but Tanjiro use his sword to block the bite, causing his sword to get stuck in its mouth. "It's stuck! I'm unable to pull it out!" Tanjiro thought looking worried. "It must have something to do with the stone structure of the canine, and it looks like its biting hard."

He then saw the other canine beginning to approach him and bite at his leg. "Crap! The other one is coming!" He tried to pull the sword out of the other wolf's mouth, but it wouldn't budge. "What should I do? Wait, what am I doing? I've sliced a boulder before, so I should be able to slice right through these two canines." He then began to use his fourth form again. "Fourth form…Striking tide! He then sliced right through the demon that was biting his sword and then delivered another strike at the second wolf slicing its head off. The second wolf began to disintegrate.

"There. That should take care of that." Tanjiro sighed. But then, he heard the woman scream as he saw the demon getting ready to devour her again. "Crap! I forgot about the woman! I need to rush to her aid quickly!" Tanjiro then began to run to the demon to protect the woman, but then, he saw the other stone wolf approaching him, but without the topper part of its head, and grabbed Tanjiro's sword with its rock hard paws.

"Oh no! The other wolf is still alive!" Tanjiro thought, as he was now in a pickle. "I need to break free from its grip so I can save the woman, but the grip feels too tight to break free! And once I am able to break free. I don't think there will be enough time to save the woman. I'm not sure what to do…"

Just then, he heard the sound of something opening from behind him. The demon was seen cackling at the woman. "Time for me to have a midnight snack!" He exclaimed. But then, he felt himself being kicked in the face, taking the top part of his head off.

When Tanjiro saw the demon get his head kicked off, he found the opportunity to slice through the paws of the canine. "Second form…Lateral Water Wheel!" Using an improved version of his second form, he spun around horizontally slicing the paws off the stone wolf, as well as slicing its neck off in the process, killing the canine.

He then turned and saw what kicked the demon's head off. "Nezuko!" He shouted, rushing to his sister's aid. "Nezuko…thank you for the help."

Nezuko gave a smile. "Mm-mmmph!" She said under her muzzle.

Just then, the two of them heard laughing as they saw the demon slowly regenerating its head. "Well well well, what have we here?" Once he finished regenerating his head, he then examined Nezuko and leaned closer to her. "Hello there my fellow demon," He said to Nezuko. "I notice that you're fighting on the wrong side. Your enemy is right beside you. Why are you fighting alongside him?"

Nezuko just gave a small growl and spread her arms indicating that she's protecting her brother. "Oh I see how this is." Said the demon. "You're just a filthy traitor aren't you? Well you ugly tramp, you made a BIG mistake siding with the ones who slaughtered many of our brethren!"

Tanjiro stepped forward. "Don't insult my sister like that!" He shouted. "She's different from other demons like you! And she is NOT an ugly tramp! She was the most beautiful girl in our hometown! I will not let you hurt her!"

The demon just cackled. "Oh what's this? You two are related by blood? Tch. No wonder you're siding with him." He then placed his hand on Nezuko's shoulder. "You're no demon, you're just another pathetic slayer DISGUISED as a demon. And you know, it's not too late to change sides…" Nezuko then quickly reacted by scratching the demon's arms with her sharp nails.

The demon cried out in pain and gripped his arm, regenerating the wound. "You little shit!" he exclaimed. "You just made a HUGE mistake doing that! I guess it has become a two against one now isn't it?" He then grabbed his two battle axes. "Well let's just make this FAIR then!" He then proceeded to swing his two axes. "Blood Demon Art! Stone Wolves!" He then slammed his axes into the ground. This time, FOUR wolves emerged from the ground rather than just two. Tanjiro and Nezuko prepared themselves. The demon cackled evilly. "These ought to distract you! Now where was I? Oh right." He then turned to the poor helpless woman. "It's time for my dinner…"

The woman stepped back and shrieked. "Nezuko!" Tanjiro said. "Protect that woman! I'll take care of these wolves!"

"Mmph!" Replied Nezuko. She then rushed to protect the woman from the demon while Tanjiro got into position to fight against the wolves.

When the demon saw the Nezuko about to fight him, he laughed in amusement as he towered over her. "I've never got to fight another demon before! So this will be real fun for me!" Nezuko's veins popped out of her forehead and her eyes turned more demon-like as she was about the fight against the demon. "Awww, what's wrong? Did I strike a nerve? There's not way a little girl like you will be able to take on a strong demon like myself! Judging by your appearance I can tell you've barely devoured any human! If any at all! I bet your abilities aren't on par with me-" before he can finish, Nezuko jumped up in the air and kicked him in the face, leaving a good chunk of his head to fly off and he fell back.

The demon was caught off guard but he his confidence remained. "Heh, didn't expect that. But still, some lowly kicks are still not enough to fully take me on…" He then began to aim his two guns at Nezuko's head. "But let's see if you can dodge this!"

He proceeded to fire his bullets at Nezuko. Nezuko quickly dodged them with her swift movements, leaping over them and changing her size so they wouldn't hit her. However, she did end up getting his by some of them, causing her blood to spill out.

Meanwhile, Tanjiro was busy trying to take out the wolves. They snarled at him getting ready to attack. "Alright." Tanjiro thought. "They're getting ready to attack, and there are more of them than before. Once they get close enough to me, I'll leap into the air, and use my second form. That will most certainly handle them."

The wolves growled and began to charge at Tanjiro. "Here they come!" He thought. He stood there, waiting for the wolves to get into a good enough position for him to strike. Once they were close enough, he then leaped into the air and raised his sword above his head. "There it is! The opening thread!" He thought, as he got into a good enough position to strike. "Second form! Water wheel!" He then spun his body around, causing his sword to strike through the wolves' necks, and slashed their heads off. Once he got onto the ground, three of the wolves disintegrated into nothing.

"There we go. That should take care of that. But…something is wrong." He thought to himself for a moment for what could've possible gone wrong during his strike. "When I slashed throught three of the wolves, I sworn I felt the thread snap towards the end of my strike. So that could mean…"

His thoughts were then interrupted as he felt something bite into his arm. He turned and saw one of the wolves biting into his arm. It appears that the wolf managed to survive Tanjiro's strike, as only its tail was slice off. "Not good!" Tanjiro thought worryingly. "One of the wolves survived! And it looks like they've got me in a hard grip! I won't be able to swing my sword to decapitate it!"

Meanwhile, Nezuko was still battling against the demon. Nezuko was delivering kicking to the demon, while demon was dodging them and continued to fire his bullets and swing his axes at them. "This girl is quick!" The demon thought. "It's hard for me to keep up with her! And since she's a demon, slicing at her is no good since she'll just regenerate her limbs!" He then proceeded to slice at Nezuko's arm with his axe, causing it to fly off of her. However, Nezuko was able to regenerate it. "I need to take care of her somehow so I can get back to eating that woman!"

"Nezuko!" The two of them heard Tanjiro shout and they turned. Tanjiro was struggling to free his arm against the wolf's tight grip. He also couldn't swing his sword since the wolf was biting on his right arm.

Nezuko saw that her brother was in danger and quickly ran to rush to his aid. The demon smirked as now this was his chance. "Perfect! Now I can get back to my meal!" He then turned to the woman and grabbed her by her neck.

Nezuko stopped running as she heard the woman shout in pain. Now she was caught in a pickle. She had to rescue her brother from the wolf, but she also had to defend the woman from the demon. The demon was about to take a bite out of the woman, but Tanjiro also dropped his sword as the wolf was biting into his arm forcefully.

Nezuko thought for a moment and then saw some of her blood on the demon's arm from their fight. She then proceeded to use her Blood Demon Art to set her blood on fire causing the demon's arms to burn. "ARGH!" The demon cried as he dropped the woman. He saw the flame on his arm and began to freak out.

This was then Nezuko's opportunity to rush to Tanjiro's aid. She ran up to the wolf and kicked it hard, causing its body to become detached from its head. The wolf's head began to disintegrate and Tanjiro clenched his arm.

"Thank you Nezuko." He said. Then grabbed his sword and got back into position, getting ready to take on the demon again.

The demon's arm was burning from Nezuko's blood and the demon tried his best to put it out. He eventually gave up and used his strength to complete rip his entire arm off, and tossed it to the ground. He then regenerated his arm and turned to the two Kamado siblings looking very angry, and then, he glared at Nezuko.

"How…are you…ABLE TO USE BLOOD DEMON ARTS IF YOU HAVEN'T EVEN DEVOURED ANY HUMANS?!" He scolded. "THAT DOESN'T MAKE ANY DAMN SENSE!" He then turned to Tanjiro. "AND YOU! WHY DO KEEP BREAKING FREE FROM MY PRECIOUS DOGS?! YOU'RE MAKING IT HARD FOR ME TO DEVOUR THIS WOMAN ALREADY!" The woman slowly backed up in fear. "THAT UGLY TRAMP WOULD BE IN MY BELLY BY NOW IF YOU HAVEN'T INTERFERED!"

Tanjiro stepped forward. "I interfered because you are harming innocent human!" He shouted. "Do you know how many have suffered because of your actions?! Some have even lost their parents because of you!"

"SO WHAT?!" The demon shouted. "Those humans had to die because they were snooping in other demons business! It's already a pain in the ass enough for normal humans to be snooping on me, but for pathetic demon slayers like you?! That is crossing the line!" He then stepped forward to his burgundy cloak. "I have had just about enough! It's time for me to go all out now!"

The demon reached into his cloak, and then pulled out a very large battle axe that he held with all four of his arms. Tanjiro and Nezuko both stepped back at the sight of it. "It's time for you two to die already!" The demon said with a scowl on his face. "And let's see if you can take on my strongest dog yet!" He then raised his large axe above his head. "Blood Demon Art…" Then, the demon proceeded to slam the axe into the ground with all of his force. "STONE WOLF!"

The ground started to shake, and the two siblings stepped back as they saw a large wolf, even larger than the other ones emerge from the ground. It then looked at the two and let out a loud roar. The demon laughed in delight. "There's no way you two will be able to take both me and my glorious pet on at the same time! Which means this woman here is doomed, and there will be nothing you can do about it!"

Tanjiro and Nezuko stepped back. They were now unsure of what to do. "Crap! This one is bigger than the last ones! What do I do now?" Tanjiro thought for a moment and then thought that if he decapitated the demon, the wolf would die too. He needed Nezuko to hold the wolf off while he would fight the demon head on.

"Nezuko! Do you think you can hold the wolf off while I take on the main demon?"

Nezuko nodded in confidence. "Mm-mmph!"

"Great! I'm counting on you Nezuko!" Tanjiro then ran up to fight the demon while Nezuko began to hold off the large stone wolf.

The demon saw that Tanjiro was about to fight him and smirked. "So, it looks like you're planning on battling me head on?"

"That's right!" Tanjiro exclaimed. "You will not hurt that woman and I will finally defeat you!"

The demon laughed. "Maybe it's about time I teach you a lesson to mind your own business!" He then swung his large axe at Tanjiro and he managed to dodge it. He got into position and began duel against the demon.

The two clashed their weapons together engaging their duel. The demon's swings had so much force in them, and it was hard for Tanjiro to keep up. So when he was unable to block them, he still managed to dodge them.

"Come on kid! Is that all you got?" The demon taunted. "You call yourself a demon slayer and you lack skill!" He swung his axe around and Tanjiro barely dodged it. Tanjiro fell back and then charged towards the demon. The two of them continued to duel.

"Ngh! This demon may not be a 12 Kizuki, but he's still pretty strong!" Tanjiro thought. "His large axe is what's giving him the upper hand! He's swinging with so much force that it's hard for me to block them after one hit!" He saw the demon preparing for another swing and he quickly dodged out of the way. The two of them then continued to clash their weapons.

"I need to find a way for me to deal with this large axe so I can properly strike him!" Tanjiro thought to himself coming up with a new strategy while he continued to duel. "I think I got it! I just need to quickly slice his four arms off so he will drop his axe, then I will go for his neck!"

"Hmph, this kid looks like he's putting up a fight, but he's still inexperienced compared to me!" The demon thought. "I wonder how much longer he can last."

The two continued to duel while Tanjiro waited for a good opening so he can strike at the demon's arms. The demon kept swinging from different directions so it was difficult for Tanjiro to find a good opening. But then, Tanjiro got an idea. "I got it! I'll use my signature move!"

Tanjiro then proceeded to leap into the air and raise his head. "Huh? What the hell does that kid think he's doing?" Then, due to the demon being off guard, Tanjiro headbutted the demon and the demon fell back. It's important to know that Tanjiro has a stone hard forehead that he inherited from his mother. So his headbutts are very painful when they hit. "Argh! The damn punk headbutted me!" The demon exclaimed.

Now that the demon was in a good enough position, Tanjiro quickly rushed over to him and leaped into the air. "Water breathing! Second form! Water wheel!" Tanjiro then spun around in the air and managed to slice all four of the demon's arms off and his battle axe fell to the ground.

"Dammit! He sliced my arms! It's going to take time for me to regenerate!" The demon then looked worried as he then saw Tanjiro getting ready to charged towards him again.

"Alright, time to finish him off!" Tanjiro quickly rushed towards the demon and was ready to decapitate him. "There it is! The opening thread!" He aimed his sword at his neck and prepared to use his first form. "Water breathing! First form!" He then swung his sword and managed to slice through the demon's neck, causing his head to fly through the air. "WATER SURFACE SLASH!" Tanjiro landed and the demon's head rolled across the ground and both his body and head began to disintegrate.

The demon was in complete shock that he lost to a mere child like him. "No…I lost?! Impossible!" He then looked at the child as he saw his body disintegrating and became very angry that he lost. Tanjiro then turned to face him. "DAMN YOU! DAMN YOU DAMN PUNK!" He scolded "WHY COULDN'T YOU JUST HAVE MINDED YOUR OWN BUSINESS AND LET ME EAT THAT WOMAN?! I WAS SO CLOSE TO BECOMING PART OF ONE OF THE 12 KIZUKI AND YOU JUST HAD TO RUIN EVERYTHING FOR ME! YOU DAMN DEMON SLAYERS JUST DON'T KNOW HOW TO MIND YOUR OWN BUSINESS!" His head then began to fade away. "I can't die! I JUST CAN'T! NOT UNTIL I KILL YOU AND GET MY REVENGE! DAMN YOU! DAAAAAAAAMN YOOOOOOOOUUUUU…." The demon's head then faded away into nothingness.

Tanjiro then let out a sigh of sadness. Even though demons like the one he just faced are horrible monsters, he couldn't just help but feel sympathetic. After all, demons were once human, and they chose to go down a dark path and there was nothing Tanjiro could do about it. He had no choice but to slay the demon, but alas, the mysterious murders that were happening will now be put to an end.

Meanwhile, Nezuko was seen fighting against the large stone wolf when it suddenly started to fade away. Nezuko looked rather confused until she realized that Tanjiro has killed the demon. He turned over to her brother and gave him a smile and a nod. "Mm-mmmph!" She said. Tanjiro couldn't help but smile back at her.

Just then, the woman ran up to Tanjiro to thank him. "T-thank you so much kind sir!" Said the woman. "I-I just don't know how I'd ever repay you!"

Tanjiro gave the woman a small smile. "Well, I was just doing my job." He said. "You're safe now, and that demon will never harm you again."

"R-right of course!" The woman said.

"Now," said Tanjiro. "You should probably head home now. It's getting late, and you wouldn't want more demons to show up, wouldn't you?"

"Right. That's sounds like a good idea." The woman then proceeded to head back to her home. "Goodbye young sir." She said and waved goodbye to Tanjiro as she left. Tanjiro couldn't help but wave back.

Nezuko then walked up to her brother. "Oh, Nezuko." He said as he saw her approach her. "You aren't hurt are you?" Nezuko responded with a soft "Mmph". Tanjiro then gave her a small smile as he patted her on the head. "Well I'm glad to hear that." He said.

Tanjiro then looked up into the sky, relieved that all of this was finally over. "I guess now the mysterious murders won't be happening anymore." He said as he looked into the stars. "Now I won't have to be worried or distracted as I train anymore."

Then, Tanjiro took off the wooden box on his back and placed it on the ground, gesturing to Nezuko that it was time to head back. "Come on Nezuko, let's head back." Nezuko then walked over to the box and shrunk down to a size so she could fit inside the box. Once she was in it, Tanjiro closed the box and then put it back onto his back and began to walk back to the Butterfly Mansion. The rest of the village began to put it's lights out as it was late and all the villagers were getting ready for bed, as a new day would approach them tomorrow.

MEANWHILE…

In an unknown location, the demon that Tanjiro had slain was seen passed out on the ground. He then slowly began to open his eyes and get up off of the ground. "Ugh… What happned?" He groaned while rubbing his head. He now looked a little bit different from how he did from before. For one, he no longer had his extra pair of arms, with now only have two. He was also wearing a burgundy kimono with some sort of wolf pattern on it. His skin now looked like it was made of pure stone as it had some sort of rocky pattern on it and his neck now had some sort of scar as if a sword was sliced across it. It took him a moment for him to realize that he was somehow still alive. "Huh? I'm alive? How is this possible?! That kid sliced my head cleam off!" He exclaimed. He looked around his surroundings to see where he was.

It appeared that he was now in some sort of city but the sky was a deep shade of red. There were also trash and garbage all over the place and the sounds of people going at eachother's throats. But what really stood out to him the most were these strange humanoid and anthropomorphic creatures who each had different appearances. Some of them looked like normal humans with different colored skin, scalera and had horns coming out of there heads, while others looked like some furry animals, and other had some sort of elemental appearance like fire or water. The demon was intrigued but also confused.

"What is this place?" He asked curiously. He decided to go ask what kind of place this was.

He saw one of the strange creatures leaning against a trash can and appeared to be smoking a cigarette, and he also had a grumpy look on his face. The demon began to approach him. "Hey! You there!" He called out.

The creature turned to him. "What the fuck do you want, asshole?" He asked irritatedly.

The demon was taken aback by the demon's vulgar tone. "Woah, looks like someone here has a vile mouth." He said looking surprised.

"Yeah, you have a fucking problem with that shitface?" Asked the creature now looking very annoyed and pointed his cigarette at him.

"Listen," The demon said. "I'm just here to ask what the hell this place is."

The creature let out a loud scoff. "Well you just answered your own question dumbfuck." He replied. "You're in hell now."

The demon was shocked when he heard this. "Hell?" He asked, looking around confused. "This doesn't look like he'll to me."

"Well it is. So deal with it." Said the strange creature. "You're here because your unfortunate ass ended up dying back on earth, and now you're stuck down here along with with all the other unfortunate sinners who lost their life."

The demon thought for a moment as the gears in his head started turning. Then it finally hit him. He died after that wretched kid decapitated him back on earth, and he ended up down here in hell, and all of these strange creatures like this one here are sinners who lost their lives back on earth for their horrible crimes. "Wait!" Said the demon. "I AM dead? Me getting my head cut off actually did kill me?"

The sinner let out a loud groan. "Holy shit are you fucking deaf?!" He said in frustration. "Yes you are! You're dead and you're stuck down here in hell with all these other assholes! Now fuck off and leave me alone already!" The sinner then went back to his smoke.

The demon was shocked from just finding this out. He then walked away from the demon as he had trouble taking in all this information. He walked through the city streets of hell, passing through the many different sinners he came across. "So… this is hell." He said to himself. "This isn't what I pictured it looking like." He examined the city streets and buildings that he came across. "I thought it was going to be a realm of eternal flames where souls burn and suffer forever." As he examined the city streets, he accidentally bumped into another sinner, causing him to get angry at him. "Watch where you're going asshat!" The demon didn't pay attention to him.

Then, he started to think about Tanjiro and how he lost to him. He then clenched his fists in anger. "But damn that kid!" He muttered. "If he had just minded his own business, I would've devoured that woman and I wouldn't have ended up down here! And also, damn all those other demon slayers!" He started to get more and more angry and he thought of the other demon slayers. "They are bastards who are always snooping in the business of poor innocent demons! They are the worst kind of human beings and only think of themselves! But the one that irks me the most…is that wretched kid!" The more he thought about Tanjiro the more and more infuriated he got. "He took away my perfect chance to get a nice meal and I am unable to take revenge on him!" He then looked up to the sky and shouted as loud as he can "I WILL NEVER FORGIVE HIM!"

He then took a deep breath and sighed and passed by a store that was displaying TVs. "If only there was a way for me to take revenge of that brat beyond the grave…" He said to himself.

Just then, he heard some sort of static noise. He turned and saw one of the display TVs were displaying static and he started to become intrigued. "Huh? What is this?" He said curiously. He walked up to the TV and then it started playing a commercial of some sort of red creature with black and white stripped horns and a black suit with a black coat.

"Hi there! I'm Blitzø! The "o" is silent, and I'm the founder of I.M.P!" said the creature on the commercial, known as Blitzø, gesturing to a logo of the 'I.M.P' company.

He then proceeded to show two images. The first one was an image of him wearing two top hats through his horns, a monocle and a fake mustache that he was twirling while standing behind a burning building labeled "Orphanage for Elderly Blind Newborn Dogs". The second image then showed him in an angel costume while happily throwing an empty coffee cup into the trash instead of the recycled bin.

"Are you a piece of shit that got sent to hell or are you an innocent soul who got FUCKED over by someone else?"

The commercial then cut to a large muscular sinner with red skin and wearing an Ohio sports jersey, and giving a testimony while Blitzø's hand is in the frame holding a sign that says "Some guy hired us!"

"After lovingly killing my wife for…" the sinner's voice then turned into a demonic tone. "FUCKING THE DELIVERY MAN!" He then returned to his normal speaking voice. "You can imagine my surprise when I wound up here, after the state of Ohio killed me!" He then gave a look of annoyance. "I really wish I could stick it to that…" He then returned to his demonic voice. "YAPPY JOGGER WHO SAW ME HIDING THE BODY!"

The commercial then cut to Blitzø holding some sort of book while two other creatures, one who was a male wearing a black suit and had white hair and black and white stripped horns, and the other was a female wearing a black tank top and some black shredded up pants, had short black hair, and two black horns with some small white lines around it, arranging some candles on the floor in a pentagram shape.

"Well, luckily for you. Thanks to our company's special access to the living world," He then made a magical gesture with his hands, causing a firey portal to appear on the floor, making the two creatures jump in surprise. "We can help you take care of your unfinished business by taking out anyone who screwed you over when you were alive!" He then walked up to the forward and fell backwards into it.

When you want somebody gone, and you don't want to wait too long

Call the Immediate Murder Professionals!

As the demon watched the commercial, an evil grin slowly started appear on his face which then started to morph into an evil laugh…

AUTHOR'S NOTE: Thank you so much for reading!And case if you're wondering about the timelines for each universe in this fic:For the Helluva side, this takes place before the events of the later season 2 episodes, as I had most of this story planned out before the release of Mastermind, and for the Kimetsu side, this takes place in between Mugen Train and Entertainment District.

There will be more chapters to come in the future, so be sure to stick around and let me know on your thoughts on the story so far!