A New Born Fire, a Kimetsu no Yaiba/鬼滅の刃 + Jujutsu Kaisen/呪術廻戦 Crossover fanfic

Hi guys, after some time i decided to rewrite this story. I hope you guys like it (i have dyslexia so if the grammar is bad sorry).

Talking = Hello

Thinking = Hello

Chapter 1: A spirit that will never dim

Summary: After the fight with upper moon three Rengoku dies only to be reincarnated into a new strange world where demons do not exist, but curses do realize he has the power to defeat these creatures he goes down the path of becoming a jujutsu sorcerer and helping as many people as he cannot knowing what horrors he will face on his journey.

"Mother, was I successful? Did I make you proud?" A fire-haired man said in a weak tone and barely remaining contusions.

The woman in front of him could only smile proudly while saying "I couldn't be prouder of you, my son." She said with not a hint of doubt in those very words.

With those words said to him, the red-haired man named Rengoku Kyojuro smiled one last time before closing his eyes forever and letting the darkness overtake his vision.

"I ju- I just wish I could've protected more people... and become stronger to save those who couldn't have saved themself." Rengoku thought to himself.

He didn't feel sad that he died protecting people he just wished he could've done more and become stronger for the people he now couldn't have protected.

Unbeknown to him someone answered his prayer "maybe it wouldn't be so bad to give you a second chance who knows what your influence will chance." The deity extended its hand and from that very hand came a bright and beautiful light engulfing rengoku till it disappeared and so did rengoku.

He opened one of his eyes, feeling the sand clinging to his body due to his wet clothes and hearing the sound of the waves that slowly reached for the lower side of his body and eventually returned back to the ocean.

"Where am I?" Rengoku thought confused on the situation he was in "Better question how I am here I'm supposed to be dead!?" he quickly tried to open his other eye and "it's fine how?" He questioned his eye was shattered while fighting upper moon three. He reached out his hand to touch the center of his stomach and to his surprise "nothing but that's impossible upper moon three punched a hole through my stomach its physically impossible to recover from such an injury?" He thought his mind overflowing with countless questions that he couldn't possibly comprehend one at a time, could he have possibly turned into a demon? No that couldn't be it he still felt the same way he always felt like a human like himself. For now, he would pause the question and take a look at his surroundings.

Using his arms to push his body upwards he checked his surroundings and what he saw shocked him buildings the size of a small mountain. He had seen such buildings when he passed through Tokyo on missions, but this made Tokyo look like a small town not to mention the bright lights flooded the city with liveliness. Rengoku could only assume that there was a special celebration happening. He contemplated on going or not since he didn't know the place, but eventually decided that it would be a good idea to go there and ask people about the place and where he currently was.

The journey to the city was longer than he would've guessed. Normally traveling long distances should have been a piece of cake for him since he is a hashira or was a hashira it was expected of him to travel long distances in a short time. But now that he actually tried using total concentration breathing to shorten the time it would take to reach the strange city, he could already feel the strain of the technique on his body "that's strange" he thought "I should be able to use total concentration breathing throughout the whole day." Rengoku thought to himself

He was about to question that later but looking around to where the city was, he saw a reflection of himself on a glass wall of a building near the city. But something was very wrong, he looked younger, but not only did he look younger he was younger "what how is that possible? I'm twenty years old." it should be impossible for him to look like and be a teenager again.

After some time, he took a closer look at his appearance in the glass of the building. He still had his muscular physic and was about 5'8 feet tall. If he had to guess his hair was also shorter and face also looked less mature. He could also see that he had different clothes on it looked weird to him it was something he had never seen before. He wore a black vest that had a hood with red and orange lines across the arms. Underneath the vest was a plane orange shirt, his pants were black with a white belt around it and his shoes were totally black with only a red line in the middle and his katana sheathed at his side.

After some time, he finally arrived at the city and from up close it was even more spectacular than he thought, bright certainly but beautiful as well Rengoku couldn't help but to form a smile on his face.

Walking further into the city he could feel the eyes of people staring at him though it was something new for him. He had always had people stare at him. His mother said that it was due to his colorful hair and his owl-like eyebrows.

Looking at his right he saw a brown-haired woman in her thirties and a child with the same hair color that he assumed to be her child looking at him with the child saying things like "mommy look, look that guy has weird hair" the child said while smiling. "Akio you can't say things like that to people its rude." the woman said to her child. Deciding it would be a good idea to ask the woman about this place he stared to walk over to them.

Eventually Rengoku and the woman came face to face and before he could say anything the woman bowed her head slightly "Sorry for my son's behavior young man he has quite the mouth." The woman said lifting her head upwards to come face to face with Rengoku again. Rengoku couldn't help but laugh "not to worry mis its quite alright if I may ask such a lively" celebration?" Rengoku asked still containing a bright smile on his face, though the woman in front of him could only give a look of confusion. "Well, we're celebrating the new year did you forget?" the woman asked while Rengoku had a look of confusion "new year? But that was last month, how could they celebrate something that already happened a month ago?" Rengoku thought in his mind "excuse me miss what year is it?" Rengoku asked hoping the woman was just making a mistake when saying it was new year. "Well, it was 2016 but we're now celebrating the new year of 2017." The woman said with no doubt in her voice "what" Rengoku thought to himself he lived in the Taishō Period of Japan it was supposed to be 1921 if it was really 2017 then he traveled ninety-six years into the future.

Thinking it would be weird to just stand there confused, he gave a quick bow and said "thank you" before leaving.

(An hour later)

Rengoku was walking down the street of what he now realized was Tokyo wondering what was going on. He should've died but he didn't, and he woke up in the future and not knowing what to do were demons even still alive or did the demon slayer corps finally manage to defeat Muzan Kibutsuji. It was currently nighttime, but he didn't feel any demons in the area sure his senses were less potent, but his senses were still many times stronger than that of any ordinary human. He continued to walk down the street, he needed a place to sleep for the night, though he could easily go sleep in the forest since traveling on missions required him to do that at times. However, that was never comfortable so he decided that a place to sleep in was better than the forest until he could somehow find a house to stay.

Looking around he saw an abandoned building, he could sleep there for the night, but he knew it was not the right thing to do but he needed a place to stay, he could already feel a drop of water falling down on him and wet clothes would really be a pain. Sucking up his honor he walked towards the abandon building and stepped through a side door that wasn't closed.

Looking around he saw a big bord that read 'looking for the best places to buy a bed? Then this is your place' Rengoku felt a wave of luck come over him "thank you kami" he thought to himself before continuing to explore the big shopping store walking around he noticed it was a very dark place with not even a spot of light showing. "probably due to no electricity coming through anymore" Rengoku assumed looking around he saw a small food stall next to the door he came through and across the food stall he saw a small toy store with big stair case going upward to the second floor eventually finding a bed that wasn't completely ruined, he laid down on it and he felt that for the first time he could finally relax in this strange place. After a moment he closed his eyes and fell asleep.

(Midnight)

*RUMBLE* *RUMBLE* *BANG*

Rengoku opened his eyes hearing the strange sounds he automatically reached for his katana, scanning the area for any potential threat that might come his way. Seeing something move he quickly got up and unsheathed his katana though after looking closer he realized that it wasn't a threat but just a stray cat probably searching for food he assumed. He got closer to the pet reaching out his hand the pet the cat but only getting pointy claw and a hiss in return "guess it doesn't like physical iterations" he assumed sensing no threat he walked away from the cat and was just going to bed again "ahh guess it was just a misundersta-" suddenly all of Rengoku's senses screamed him to move and avoid the attack that would kill him if he did not move. "MOVE, MOVE, MOVE." He screamed at himself.

Jumping upward he tried to look down to get a look at the thing that attacked him only for him to be sent flying into the food stall due to a punch to the right side of his face.

"How is that possible? Is it a blood demon art? No, I would've sensed a demon coming my way, this is something entirely different?" Rengoku thought as he was send flying to the food stall leaving nothing but a pile of dirty old wood.

feeling the air leave his stomach and the pain at the right side of his face he couldn't help but grown "ignore the pain for now I need to focus on the fight ahead of me." Rengoku though pushing his body onto its feet, now having the chance to analyze the creature that attacked him. It seemed to have a muscular human-like appearance with grey-like skin and two long stretchy arms while also having claws instead of hands and a height of about 6'6 feet tall thought that wasn't the thing that disturbed rengoku he had faced demons much more disgusting than this creature. It was the dark aura that the creature put out.

Having taken a good look at the creature Rengoku held his katana firmly and breathed in as much air as his body could handle while taking a stance that his body took many times.

"Flame Breathing First Form: Unknowing Fire"

End of chapter

Wow damn that was fun to write sorry if it felt slow or if I didn't execute it good, but this is my first time writing in a long time the first time I wrote this I had Rengoku immediately thrown into the jjk world without him processing anything, so I wanted to change that and if your wandering about the time line this takes place after jjk 0 and season 1 of jjk begins in 2018 so rengoku has about one year before the events of season 1 begin hopefully you all had as much fun reading this as I had writing it see you next time bye.