When the Lights Fades

Act I, Chapter 0 : When the newborn Awakens

As soon as Muzan's defeat was celebrated, a wave of panic settled in Giyuu's heart, who was afraid for Tanjiro's health, but also in the hearts of Tanjiro's friends.  Tanjiro, who had fought alone against Muzan, was unconscious. The Water Hashira began to advance towards him and then lowered himself to check if he was alive. He was breathing, nothing else.

"Tanjiro!!" A voice was screaming, it was Nezuko, his sister who had regained her humanity not too long agao but long enough to have witnessed the battle. The sight of her unconscious brother, with one arm less, could only make her cry. She knew that crying wasn't going to get things done but she couldn't hold back. Her brother was everything to her. It was him who protected her all the time, it was him who always talk her when she was sad, it was him who made sure if she didn't need anything, it was him who - was her beloved brother.

Inosuke and Zenitsu, were simply in shock, but also under admiration, Tanjiro had achieved the impossible, beating Muzan and alone... a real exploit but with a cost...

--
Tanjiro began to regain consciousness; he raised his head and began to open his eyes slowly. Instead of their usual color, Tanjiro's eyes had a crimson color and pupils similar to a feline or simply similar to... 'him'.

Giyuu didn't have time to react when he fell unconscious. Everyone was shocked, Tanjiro, the kind and gentle Tanjiro had become a Demon and had managed to knock down an Hashira in one hit. No one moved, probably because of the intense chock and Tanjiro took advantage of it. He jumped on the highest point of the building and analyzed where he was. After a few moments, he nodded and whispered "Blood Demon Art: First Form, Fukkatsu."  A mass of clouds began to cover the sky, as if the night had begun. A circle of ritual began to form itself and a blinding light emanated from it. While the Ritual circle was formed, Tanjiro took the opportunity to analyze the faces of the people present and determined their 'specialty'. 

Once the circle was finished, figures began to come out of it but with the blinding light still present, it was impossible to know who and even how many they were. No one reacted, either out of fear or surprise. The light disappeared and the figures could finally be visible. Muzan, Kukoshibo, Douma, Akaza, Hantengu, Nakime, Gyokko, Kaigaku, Daki, Gyutaro, Rengoku, Shinobu, Muichiro, Mitsuri, Obanai, Gyomei, Genya and even Ubuyashiki were lying unconscious on the ground. In short, Tanjiro had brought back to life Muzan and the Upper Moons as well as the former ones with the Hashiras that died in battle.

Everyone was... surprised. Tanjiro had brought everyone back to life... The slayers were delighted that their allies had been brought back but they were also stressed to see also the Upper Moons present.

Zenitsu, was more than glad, his brother had also been brought back to life! He regretted having killed him with his own hands but, could see him again, spoke to him again even, but...  Kaigaku was a Demon, it was no longer possible...

Tanjiro, who was watching from above, snapped his fingers and the moons disappeared and the humans woke up but a Demon was still present, Kaigaku. Not that Tanjiro didn't manage to teleport him but rather wanted to see something that could entertain him.

--
When the Hashiras woke up, everyone ran towards them and... fell on them to hug them while crying? Tanjiro looked at them curiously. But what he saw further awayfrom the Hashiras intrigued him even more.

When it was Kaigaku's turn to wake up, he was surprised to see Zenitsu hugging him while crying.  "You're alive, I'm happy..." Zenitsu? Happy to see Kaigaku, his enemy, alive? "Why... Why did you decide to become a Demon? I know it's not because of 'that'... So tell me, please..." Kaigaku was thinking. Should he reject him and flee? or should he try to talk to him? But... why had he really decided to become a Demon?

"Because I was jealous, jealous of you... You... were Grandpa's favorite, you quickly made friends and you got along very well with them while I... I was nothing. I had no one to talk to, and when I finally met someone, these people always walked away, saying that I was nothing, and I didn't deserve to live... I... just wanted to be recognized at my true value I think... Sorry... If only I could go back and treat you well like I should have, maybe we could have gone on a mission together who knows." he said with a sad smile.

Zenitsu, who had listened to him silently, smiled. He let go of Kaigaku and looked him in the eyes and smiled, his apology was sincere, he could see it in his brother's eyes but a problem remained, Kaigaku was a demon. What could he do?  But wait...! If Tanjiro was able to revive him, could he make him human? It seems impossible but who knows? He raised his head and looked for Tanjiro as soon as possible. Once found him, Zenitsu begged him to help him and that he would do anything.

Tanjiro, who was looking down on them, said nothing but displayed a smile in the corner, a smile somewhat... terrifying. A kind of tentacle bone came out of his back and it rushed in Kanao's direction and stole an object from her. It was the serum that allowed a Demon to become human again, she had it on her just in case, and then it is, the serum was stolen. She tried to get it back but in vain, the tentacle was far too fast for her who was tired after her fight against Douma.

Tanjiro analyzed the serum through his tentacle and directed it in Zenitsu's direction where it stabbed Kaigaku in the neck with the serum's needle and injected it into him. The young Demon cried out in pain and began to feel like he was burning from the inside, the pain he felt was worse than the one he had experienced when Muzan had given him his blood but he had to resist, for his brother's sake.

The screams persisted for a long time; all the people present could do nothing but watch. A few seconds later, the screams had stopped. Kaigaku's demonic marks began to disappear, the number in his eyes had faded, and Kaigaku... had finally become human again... The serum had really worked! But it was the one and only one available. The serum couldn't get duplicated, but it didn't matter now. "Kaigaku, you're human! You're really human!" Zenitsu shouted with joy. The old demon couldn't believe it, he really had become human again! He raised his head and looked for Tanjiro to thank him but tanjiro was still watching them, his crimson eyes were shining and they were observing them, as if they were able to see absolutely everything.

It was the turn of the other people to look at Tanjiro. He had become a Demon, but... he had saved the Hashiras and their master... Why did he do that? Out of kindness? Amusement? Impossible to know. He began to redo his smile in the corner before jumping in the middle of the crowd and created a crater when he landed. He started to create a kind of floating sphere that he projected into the sky.

"Blood Demon Art: Second Form, Kako ni modoru" (Back in time)

Following this, the sphere stopped rising itself into the sky and began to grow bigger and bigger before exploding, engulfing the entire country with a white light before disappearing without a trace.

--

Nezuko woke up, she had dreamed of something crazy but she couldn't know what, she had simply forgotten. '.. ! I have to go home! Quickly, a note!' She thought in a rush. She wrote a note to Mr. Saburo, thanking him for letting her sleep at his home and then hurried to her house, she had to hurry, she had to takecare of her family but also her brother Tanjiro who was sick the day before.

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Kamado Tanjiro

Status: Alive
'Race': Demon [?]
Affiliation: Unknown
Blood Demon Arts:

Fukkatsu (Resurrection):
Allows the user to revive any dead person, can not exceed a period of time equivalent to 2 years. Cost a very high amount of energy, is really dangerous, deadly even.

Kako ni modoro (Return to the past):
Returns a large delimited area back in time, cannot exceed a return too large compared to the energy of the user. For example, going back 5 days in time would require 10 days of rest. Be careful throughout uses.