Coco: Hey, guys, it's me Coco. And I'm here with another new story. Which I hope you will enjoy. I've been working on this for a while since I wasn't sure what kind of OC I wanted to use or what kind of breath. Like an existing one or make my own, ya know? I went through quite a few different characters and breaths before finally settling on Tatsuo!

Anyway, as always, I hope you enjoy!

The Demon Slayer Corps. They're numbers are few. A band of slayers taught a special breathing technique to slay a certain type of demon. Not the demons of old born from nature and of animals. These demons had once been human and their progenitor born from an elusive flower with unique properties.

Their staple food—humans. They hunt and kill them. It is unclear when and where they first appeared. Incredible physical prowess. Their wounds heal almost instantly—flesh completely restores itself—severed limbs regenerated. Some can shapeshift. Some have other powers. They can only be killed by sunlight or decapitation by a special sword.

The Demon Slayers fight these demons with mere mortal bodies. As humans, wounds are slow to heal, and their lost limbs are unable to grow back. Nevertheless, they fight to protect and defend humanity.

"Mother, Big brother, where are you?!" A young girl cried as she tried to search for her two missing family members amongst the chaos.

Buildings were burning around here and people running to try and escape the demons who came to terrorize them. The girl should have been trying to flee with the others, but she kept moving farther into the pandemonium unwilling to give up her search. Her father was somewhere amongst the fray trying to slay as many demons as he could with his fellow slayers. Her younger siblings had been taken by her grandmother to safety, which only left her mother and older brother unaccounted for.

"Mother!" The girl tried again. "Big brother!"

She received no replies, but she soon spotted her family's home as she kept pushing forward. She saw the door was missing and she saw blood smearing the sides of the doorway. The red liquid was also splattered heavily across the ground there, and she felt her heart drop. She rushed forward gripping her the hilt katana in her hand as it remained sheathed at her side. She ran into the hut without hesitation while instantly spotting the back of her older brother.

"Ryogi!" She called. "There you are. Where's Mother?"

At first, he didn't reply and as she was about to ask again, his body slowly pivoted around. Her eyes widened as she spotted the blood all over his clothes and the large gashes and holes in his torso and chest.

"Tat…suo…run…" He managed to say before falling forward onto the ground.

As he hit the surface, his blood splattered across the dirt floor. Some of it hitting Tatsuo's feet, which caused her to jump back.

"R…Ryogi." She whispered as tears started to well up in her eyes. "Big brother!"

She went to rush to his side even if she knew there was nothing, she could do to help him. However, when laughter entered the air, she came to a quick pause. Her entire body tensed as her trembling hand tightened its hold on her katana.

"Who's there?" She demanded to know as she drew her sword. "Come out!"

The laughter increased before a figure stepped out of the shadows. Tatsuo felt bile rise into her throat as she took in the figure before her. A beautiful woman with long brown hair and blue orbs was looking back at her. Her kimono covered in blood. Some her own…and the rest her son's…

"Mother…" Tatsuo said. "…No…this can't be happening…you can't be…"

The thing that had once been her mother smirked cruelly at Tatsuo while slowly stalking forward. Tatsuo took a step back as her heart hammered in her chest. It was almost so loud she could hear nothing else. Not the screams and fighting outside. Not the sounds of the buildings collapsing in on themselves once the fire did its worst. Nothing else…until it spoke.

"My, my," It hummed. "You look even more delicious than the last. I wonder…how you'll taste."

It then launched itself forward with Tatsuo letting out an anguished cry as she swiped her weapon forward.

"Flesh! Give me flesh!" The demon screeched as it charged at its prey.

It jumped at the figure before it, but the figure spun on their right heel last second to dodge the demon. In a flash, they drew their sword as the demon turned towards them once more. It tried to make a bite at their shoulder, but the figure was too quick as they easily sliced the demon's head clean off in one fell swoop.

'Breath of the Dragon. First Form: Breathing Fire.'

The demon gagged with its eyes widening as its head fell from its body. As its body fell towards the ground and was crumbling away, the one who killed the demon swiped their blade out to the side to rid it of the blood.

"You damn girl!" The demon screeched as it was dying. "I'll kill you for this."

The girl, who the demon cursed, scoffed as she sheathed her weapon. She turned her eyes onto the wilting demon. The girl appeared to be fifteen to sixteen years of age and had a slim, toned figure as if she trained daily. Her dark brown hair was cut short with a single small braid in the front. Her eyes were a piercing blue, and her a deep tan.

She wore a backless, sleeveless top with a cropped red haori that had scale like patterns across it. She then had on black fingerless gloves that went pass her elbows and instead of wearing sandals, she wore black boots, which her black hakama were tucked into, that went up to midleg on her. On her waist there were two katana with one of the katana blades being much shorter than the other.

"It'd be interesting to see you try, demon," The girl—Tatsuo—said. "Considering you're turning into ash."

The demon just gave a final snarl before complete turning into ash. Another screech sounded behind the young girl, who managed to flip up and over her attacker as he came at her from behind. As she was in the air, she drew her swords from their sheaths.

'Breath of the Dragon. Second Form: Dragon Hunt!'

She twisted her body around while she was still in air using her two blades in a scissor like motion, she sliced the demon's head right off. Its head flew from its body with its blood spraying everywhere as the girl landed on her feet onto the ground.

'Master was right,' Tatsuo thought as she looked around. 'There really are too many demons to count on this mountain.'

Mt. Fujikasane really was crawling with demons. Of course, it was, as this was the place where those who wished to be Demon Slayers came for Final Selection. If they pass, they join the corps. If they fail, well, that means they've fallen prey to the demons who live on this mountain. Though most of the demons here were starving and weak. The only thing they had going for them was the fact that they outnumbered the humans in this trial twenty to one, but it would seem even starvation couldn't bring the creatures to band together to try and gain food for themselves.

Tatsuo hasn't been taking the trial long, but has had to cut down several demons in that time. Some had been feeding when she ran across them, and while she couldn't save the examinees from their grizzly fate, Tatsuo had killed the demons. She supposed it was the least she could do for the fallen. Besides, it was her duty to end the lives of the wretched demons. Being a Demon Slayer was in her blood. Her family has been part of the corps since the very beginning, and she carries on their legacy…alone…as the last of her family.

'I won't fail in this exam,' Tatsuo thought in determination.

Tatsuo came out of her thoughts as she looked up at the sky to see the sun starting to peek over the horizon. It would seem dawn really was approaching, which means she'll finally be able to get some rest. Even if not too much as it was best to keep moving as much as possible. She'll give herself at least three hours since she didn't need to deprive herself from sleep either. Though she'd have to remain alert until a place to settle was found.

Demons could still try for a desperate last-minute attack if they were hungry enough. And there was no way she was going to let a demon get the drop on her while she was on this mountain. Her master wouldn't let her hear the end of it. Not to mention that she didn't want to disappoint him either. Tatsuo then looked up once more as she heard a roll of thunder.

"Looks as if the rain is about to move in." Tatsuo said, which meant she needed to hurry and find a place to camp.

However, before she moved on, Tatsuo straightened up when hearing footfalls not far from her. She turned her head while stepping back into the side of the tree to hide herself. Tatsuo didn't think it was a demon making that noise as it wouldn't be moving so slowly. Not with dawn breaking over the mountains. However, it was best to make sure. She peeked around the side of the tree with her right eyebrow rising when seeing it was a boy who seemed about her age.

He seemed exhausted and he had an injury on his head that seemed to be bleeding. It seemed a little deep and it seemed as if he hasn't even tried to take care of the injury. An injury like that could easily become infected and the fact that it was an injury to the head made things worse. Just then the boy dropped to the ground, which caused Tatsuo to shake her head. This kid just seemed like the reckless type.

"I suppose I should help him out." She said though she didn't sound pleased.

Tatsuo hadn't really planned to help out her fellow examinees like this as her master had told her to worry about herself. That the test was hard enough to survive on one's own let alone worrying about someone else. But she also knew walking away wasn't an option. She let out another sigh.

Tanjiro groaned feeling a warm sensation traveling through his body as he began to wake. His eyes slowly opened to see what looked like the ceiling of a cave above him. He also noted the smell of smoke and the crackling noise of a fire. He was confused for a moment as he tried to recall what had happened before he had fallen asleep. As the memories came rushing back, he gasped while sitting up in a hurry. However, that just made him feel dizzy and caused him to groan once more as he clutched his head. He reached up to hold his pounding cranium, which was when he noticed the cloth tied around the wound he had received earlier.

"I wouldn't move around too much if I were you." A voice said.

He turned quickly to see a girl who seemed about his age or a bit older. She was sitting next to the fire he had smelled moments earlier as she was feeding it more wood. She looked up at him with her pale eyes meeting his confused gaze.

"You have quite the nasty bump on your head, pal." She said pointing at her own head. "So, any sudden movement is bound to make you dizzy, understand?"

Tanjiro just blinked at the girl as she returned to tending the fire. Once she seemed satisfied with it, she sat back.

"Who…who are you?" Tanjiro asked.

The girl blinked at him as she tilted her head slightly at his inquiry of her name.

"My name is Sano Tatsuo," She replied. "Who are you?"

Tanjiro stiffened while remembering his manners. It had been rude of him to ask her for her name when he had not even given his own. She had even been kind enough to help him.

"Oh, forgive me," He said. "I'm Tanjiro. Kamado Tanjiro. Thank you so much for helping me, Tatsuo-san."

Tatsuo hummed in reply as she put her hands behind her head and leaned back into the rock wall behind her. It was then that Tanjiro took in their surroundings. It would seem as if Tatsuo brought him to a cave of some sorts. It had him eyeing the back of the cave worriedly. Though it was during the day it was dark outside due to the rain. Not to mention demons could be lurking within the depths of the cave.

"Don't worry," Tatsuo said. "I already searched the cave for demons after getting you settled. Now I suggest you get some rest while you can, Tanjiro."

Tanjiro nodded his head supposing he could relax even if just a little bit. He wasn't sure how much time has passed since he passed out though.

"You haven't been out long." Tatsuo answered his unasked question. "A few hours at best. Though I was expecting you to be out longer considering the condition your head is in. Leaving an open wound like that unchecked is kind of stupid, ya know?"

Tanjiro reached up to touch his head once more. Yes, he supposed he had been foolish to leave it unchecked for so long. He's just constantly been moving since the exam started and he didn't have any kind of medicine or bandages with him. When entering the exam, examinees were allowed two things really, which were the clothes on their back and their weapon of choice to fight the demons. Which had him wondering what Tatsuo used to bandage his head. He looked back at the girl while noticing her haori had only one sleeve and the other seemed to have been ripped away. His eyes widened a fraction.

"Is there something wrong?" Tatsuo asked when seeing his expression.

"No, it's just…I'm sorry for all the trouble," Tanjiro said looking guilty. "You even ruined your clothes to take care of me…I apologize."

Tatsuo waved off his apology as she settled back even more into the cave wall to get comfortable.

"Clothes are replaceable." Tatsuo said. "A person is not."

Tanjiro, who lowered his hand once more to his lap, seemed a bit surprised by her statement.

"You may be some stranger to me, but to someone else you must be important," Tatsuo continued. "And as I said, clothes can be replaced. I can get a new haori after the Final Selection. However, once you are gone, you are gone, which is why you need to be more mindful of taking care of yourself. You don't want to make those who care for you worry, do you? You have to be more careful in the future."

"I…I will!" Tanjiro said nodding his head. "Thank you, Tatsuo-san. I will repay you; I promise!"

Tatsuo snorted at Tanjiro's earnest statement as he gave her a look of completely sincerity.

"You can stop with the formalities." Tatsuo told the boy. "We appear to be the same age, so there is little need to address me so formally."

Tanjiro blushed slightly as he guessed she had a point. He was just trying to be polite.

"Tatsuo, then." Tanjiro said. "Thank you very much, Tatsuo."

"Are you sure you want to head out on your own?" Tatsuo asked as she and Tanjiro stood at the mouth of the cave.

It would be getting dark again soon, so it was must to make some distance before that happened. Tanjiro, who was placing his sword in his sash, nodded his head with a smile on his face.

"Yes," Tanjiro said. "I'll be fine. Besides two humans traveling together would probably attract more demons."

Tatsuo knew he had a point, and if he was certain he'd be fine then she wasn't going to stop him.

"Alright," Tatsuo said. "Well, good luck, Tanjiro. I hope to see you at the end of this."

"Same here," Tanjiro said. "I still need to repay your kindness, so I hope to see you as well."

Tatsuo shook her head thinking the boy was worrying too much about 'repaying' her. But she didn't voice this as she waved goodbye to Tanjiro. They then went their separate ways with Tatsuo wanting to finish the exam and return home to her master.

Tatsuo let out a breath as stood amongst the others who had passed the exam back where they had started. The test was finally over. She got through it without any injuries on her part, but those demons were starving. Not real threats.

"Still, I passed," she said to herself.

She then walked forward stand at the back of the group of remaining examinees. As she looked around, she saw there weren't many people here. Just herself, Kano, a guy with a large scare across his face, and a boy with odd yellow hair with orange tips. She frowned slightly.

'He didn't…make it?' She quietly pondered as she didn't see Tanjiro.

She sighed feeling a little bothered at the thought the nice boy had died on this mountain. However, just as she was thinking that, she heard footsteps behind her. She turned her head with her eyes widening slightly when she saw Tanjiro. He looked tired and a little dirty and his headwound was bleeding through what looked to be the new bandages around his head, but overall okay.

"Tanjiro, you made it." Tatsuo greeted the boy.

Tanjiro seemed relieved to see her as she stepped forward with a smile on his face.

"Tatsuo, you're here too." He said then looked around at the few others.

She could see in his expression that he was surprised with how little passed the Final Selection. Honestly, from what she's been told, five people passing was quite the impressive number.

"He's gone," Tanjiro murmured as he looked down in guilt. "And all because I blacked out. I couldn't save him."

Tatsuo wasn't sure who Tanjiro was speaking about. Though it was most likely another examinee. She wondered if she should try and comfort him, but she was distracted when the blonde-haired boy spoke.

"I'm gonna die," He murmured. "I'm done for. I survived for now, but soon enough I'm dead."

Tatsuo's brow quirked at his words, but made no comment as the two children from before appeared on the stone platform in front of them.

"Welcome back, everyone," They greeted in unison.

"And congratulations," The white-haired child—Kanata—congratulated the survivors.

"We're pleased to see that you're safe," The dark-haired child—Kiriya—added.

Tatsuo lightly smiled at the pair as they stood with small smiles of their own as they looked to the passing slayers.

"So, I made it back alive." The boy with the scar cut in. "What do I do now? Where's my sword?"

Tatsuo shot the boy a look for being so rude to Kiriya and Kanata considering who they were. Either this boy didn't know of their importance or was just plain rude. Probably both.

"Patience, we must first issue you all uniforms," Kanata said. "We will start by taking your measurements. Next your rank will be engraved on the back of your hand."

"For your reference, there are ten ranks in total," Kiriya added.

"Kinoe," Kanata said.

"Kinoto," Kiriya said.

The two going back and forth as they named all the ranks from Kinoe down to Mizunoto.

"You all start at Mizunoto," Kanata explained. "This is the lowest rank in the Demon Slayer Core."

"And our swords?" The scarred-boy asked again.
"In a moment, you'll be able to select the ore that will forge your swords," Kanata assured him. "However, it will be 10 to 15 before the weapons are ready for you."

The boy didn't seem pleased with this at all as he let out a grunt of annoyance.

"Really?" He grumbled.

"But first," Kanata began before clapping her hands.

At the sound, Tatsuo heard cawing and looked up to see Kasugai Crows flying in. Tanjiro gasped as one landed on his shoulder in surprise as Tatsuo held out her arm for her crow. It landed on her arm and she stroked its feathery chest causing it to coo.

"Now that you're Demon Slayers, you must each be assigned your own Kasugai Crow," Kiriya told them.

"We get crows then?" Tanjiro asked. "What for?"

The Kasugai Crows are primarily used to facilitate communication," Kiriya explained.

"Wait…crows?" The blonde asked. "Isn't this a sparrow?"

Tatsuo looked over and almost chuckled when seeing the boy indeed had a sparrow on his hand instead of a crow. Said sparrow chirped at him while fluttering its wings.

"I don't need this crap!" The scarred-boy snapped as he slung his crow from his arm.

He then growled as he walked forward towards Kiriya and Kanata, which had Tatsuo stiffening.

"Who the hell cares about some stupid crow?" He asked.

He reached towards Kanata, but before he could touch the girl, his hand was smacked away. Those gathered looked on in surprise as it was Tatsuo who intervened. The boy glared at the girl who glared back.

"You even think about touching her again, I'll break every bone in your body," Tatsuo threatened. "Show some respect."

"Che, respect," The boy spat as he grabbed the front of Tatsuo's haori. "Just get out of my way! I want my sword! Give it to me before I get angry! The color-changing katana. I want it now; do you hear me?!"

Tatsuo didn't seem worried at all by his shouting and was ready to start breaking bones. However, Tanjiro appeared at her side while grabbing the angry boy's arm.

"Take your hand off her," Tanjiro told him firmly. "Or I'll break your arm, now!"

"Who the hell are you?" Angry boy asked as the blonde was panicking in the background. "Give it your best shot."

He obviously didn't think Tanjiro would even go through with his threat let alone manage to break angry boy's arm. Tanjiro took a break before making his grip painfully tight on angry boy's arm. The boy seemed surprised by the sudden pressure as his bones groaned in protest. He then cried out as Tanjiro nearly snapped his arm right then and there. The boy let go while stepping away to hold his now injured arm. He glared at Tanjiro as the boy moved in front of Tatsuo and Kanata.

"Are you finished chatting with each other?" Kiriya asked while completely unbothered by the violence and disruption.

Kanata was unbothered as well as she moved out from behind Tatsuo who was still glaring at the angry boy.

"Yes, my apologies for the disruption," Tatsuo said as she looked up at Kiriya. "It won't happen again."

Kiriya only nodded in reply before he and his sister moved to the table behind them. They removed the clothe to reveal large chunks of raw ore laying on the table.

"Now the time has come," Kiriya said. "Please select an ore for your sword. The steel you will use to protect yourself and annihilate countless demons will be that of your own choosing."

Tatsuo and the others stepped up to look over the ore in front of them. She honestly wasn't sure what to pick. She wasn't an expert when it came to ore. She supposed she would just have to trust her instincts and hope they lead her to the right choice. After all, she needed some kind of weapon, as she had to return these borrowed blades. She then blinked when Tanjiro stepped forward with complete certainty on his face. He reached forward and chose his ore and as he moved out of the way, Kano stepped forward as well. After she selected her ore, Tatsuo stepped forward. She stared at the ore in front of her before reaching for it.

'This is the one,' She decided. 'The one that will make my swords.'

Tatsuo let out a long sigh as her home finally came into view. She had no idea she was so tired until making the journey home. She was ready for a nice rest and some home-cooked food. She made it to the door while sliding it open.

"I'm home," She called out as she sat down on the higher platform that went into the house.

She was taking off her shoes when she heard hurried footsteps coming her way. She then gasped when she was tackled from behind and sent sprawling into the floor.

"Tatsuo-chan!" A familiar voice cried as Tatsuo was being crushed in a bone-crushing hug. "You came back alive!"

"Ah, Suma-san, I can't breathe!" Tatsuo said as she struggled in the woman's grip.

Suma was then yanked off of her by a angry-looking Makio, which allowed Tatsuo to take in a lungful of air.

"You idiot, don't kill her after she finally made it home!" Makio snapped at the woman.

"I was just worried about her!" Suma said. "And, Tatsuo-chan, I told you not to be so cold with Nee-chan! Waah!"

Tatsuo, who sat up on the ground, sighed while rubbing the back of her head. She kind of wishes she had taken longer to come home. It was always so hectic here. She then finished taking off her boots to place beside the others' sandals. She stood up while moving away from the two arguing in the entryway. She stepped up into the main living area of the house as Hinatsuru joined them as well.

"Tatsuo, we're glad to have you back," She greeted with a kind smile.

"It's good to be back…I think," she said as she glanced over her shoulder to see Makio now had Suma in a headlock.

Hinatsuru chuckled in agreement before turning her head as the head of the family made himself known. Tatsuo looked up at the tall figure of Uzui Tengen—her master.

"Master, I'm home," she said. "And with no injuries as promised."

"As expected of my flamboyant student," Tengen said with a smirk. "Welcome home, Dragon."