Chapter 17: The Demon called Muzan.

Kibutsuji Muzan was born in Japan's Heian era, plagued with a constant struggle to survive on account of his frailty. His heart stopped multiple times in his mother's womb, and when he first entered the world, he was deemed stillborn, having no pulse and not breathing. When he was taken to be cremated, he escaped death by releasing his first cries.

Throughout his young life, he struggled with illnesses and that led to his THANATOPHOBIA <fear of death>. As a young man, Muzan was diagnosed with a disease that would kill him before he reached the age of 20. The doctor treating Muzan gave him a special prototype medicine, but it appeared to have failed. Enraged by his worsening condition, Muzan killed him.

Only after killing the doctor did he realize that the medicine was actually working and had helped him acquire a strong body. He realized he needed to consume the flesh of humans to survive but was not bothered by this fact. His new and more serious problem on the other hand, was his inability to be under the sunlight, as doing so burned him severely.

It was during this moment that he truly regretted killing the doctor before he could have finished his treatment with his "Blue Spider Lily" medicine.

He searched the entire country for the flower, but couldn't find it. Due to this, Muzan started to create more Demons and planned to spread them in the world, hoping that one of them would eventually find a way to overcome the sun or at least help him on his quest to find the Blue Spider Lily.

This desire to be in the sun again became his one true goal and he spends hundreds of years chasing this obsession. In his early years as a Demon, Muzan settled down with five different women. However, because of his lack of empathy and sensitivity as a demon had driven them all to commit suicide.

Around the Oei era, Muzan found a young girl named Tamayo, who was afflicted with a disease that threatened her life. She encounters Muzan and, wishing to see her children grow up, allowed him to transform her.

Unused to her new body, she inadvertently killed her own family to survive, as well as another group of people. This decision haunted her to no end and she became resentful and hateful of Muzan. But due to Muzan's immense power, she was unable to kill him with success.

Muzan had enslaved Tamayo and she had followed him around as a dutiful servant from then on. Some years later, he finds Michikatsu Tsugikuni, a marked Demon Slayer and user of the Moon Breathing style. Michikatsu wanted to become more powerful than his brother and loathed the fact that his status of being marked meant his life would soon end. Muzan issued a compromise; he wished to have a breath using Demon and in return, he could live forever and perfect his skill. Michikatsu had agreed to the proposal and Muzan gave him an extremely high concentration of his blood, emerging three days later transformed and taking the name Kokushibo.

Later, Muzan and Tamayo would encounter Yoriichi Tsugikuni, who was Michikatsu' younger twin brother and another Demon Slayer. The moment the two met, Yoriichi sensed Muzan's malice and anger, comparing him to boiling magma. Simultaneously, Muzan found nothing in Yoriichi that resembled something dangerous and didn't fear his opponent. Already satisfied having Kokushibo as his subordinate, Muzan tried to kill Yoriichi without warning. He, however, was able to dodge the blows and discerned Muzan's weak spots, seven hearts and five brains that move freely around his body.

Yoriichi combined all his forms into one strike and turned his blade bright red, enabling him to cut through all of Muzan's weaknesses and overpower him. For the first time in his life, Muzan became stunned, unable to heal, he sat in a pool of his blood and angrily stared at Yoriichi, ignoring his question on what he thought was the value of a life.

When Yoriichi moved forward to kill him, Muzan used the remains of whatever power he had left and divided his body in a powerful burst. Though Yoriichi was able to destroy nearly all the fragments, the pieces he missed escaped and allowed Muzan to regenerate again.

Muzan was deeply scarred by this encounter and with Kokushibo's assistance, the two slaughtered anyone who used Sun Breathing, in the hopes of preventing another Demon Slayer that had the power to kill him. They were almost successful and able to nearly exterminate Sun Breathing entirely.

Greatly fearful of the man he considered the real demon, Muzan never directly confronted the Demon Slayers again and sent demons to do his bidding for the most part. He remained fearful of Yoriichi even after his death, even to this day.

In time, Muzan eventually succeeded in creating his faction, which would eventually become known as the JIU NI KIZUKI. He transformed multiple demons and gave them the chance to join his group, rewarding them with a larger share of his blood to make them more powerful.

Split into two groups of six known as the Upper Moons and Lower Moons, the Uppers remained unchanged for centuries. The Lowers on the other hand, constantly changed as they were frequently killed by the Demon Slayers, to his growing disappointment.

The Kizuki who he personally transformed were Kokushibo, Akaza, an apathetic cult leader, a prolific and henious criminal, a dying murderer, a frail young boy and a young man who he initially devoured but eventually transformed. More demons would eventually join, such a brother and sister pair of siblings, a twisted and murderous musician and a former Demon Slayer.

"This is the story of The Demon called Muzan Kibutsuji, now tell me what is it that you wish to do, Zenitsu Kuwajima?" Muzan said as he changed back to his male version.

"You have two paths to choose from, either I end your life with my hands and the tale ends right here or I return your humanity back and let you live a peaceful life. I can promise that your body will be as good as any other healthy person, but with time you will age and one day, die and leave this earth. How about that?" Zenitsu asked.

"Do you really think that I can live a normal life? The slayers will just let me go when they know that I am no longer the strong King of Demons they did not dare to face. Do you really think that there is salvation for someone like me?" Muzan spoke in a sarcastic manner, while his voice was slowly breaking in pain.

"Salvation can't be given out like sweets Muzan, only when you are at peace with yourself, can you find what salvation is. Tamayo-san is a human right now, you two spent a long time together and that's bound to mean something at least. I know that she hates you for the death of your family, but it's just nothing more than her denial to accept that her choices led her to that end and she points all the blame to you." Zenitsu said as he sheathed his blades.

"You mean to say, that I turn into a human and live out my life with her. Are you an idiot or just naïve?" Muzan growled, while thinking about the idea which he personally was giving a lot of second thoughts.

After a while, he reached to a conclusion that he would not survive unless he takes Zenitsu's offer to live the rest of his days as a normal human.

"Alright, I will kill all the demons alive and accept the offer you propose. But you must know that you being alive after this would only complicate things further, even if you are celebrated and revered as the RAIBASHIRA, the saviour and hero of the mankind, your strength will lead you to be ostracized. They will fear you, like they feared me, they will hate you like they hate me and maybe one day you will not even get the kindness you showed me." Muzan said with a sympathetic gaze.

The next minute, all the demons, those that were fighting and those that remained hidden fell down like puppets that had their strings severed.

The slayers had simply understood that the scene before them was caused by the death of Muzan, they knew that they had won the war. They celebrated with cries of victory, cheers and tears brought home the beautiful gift of victory they received.

"You don't have to worry about that, for you will live in my stead. Take my form and live on, don't get caught into any messes again and just promise me one thing, take care of Jigoro Kuwajima, be kind to him, love him and respect him in my stead. Stay beside him in his last days and help him pass on with a smile on his face." Zenitsu smiled.

"You, why go to such lengths for someone you don't even know?" Muzan asked in disbelief.

Zenitsu smiled, "this time, let me show you kindness and in turn you can be kind to others. As long as you love others, you will be loved in return." Zenitsu gave a vial of antidote to Muzan.

The demon who thought that he would never again see the light of day, the demon who will never be understood, or accepted, found acceptance, he found kindness, he found warmth after the long years of his pitiful existence.

Zenitsu smiled and joined his palms.

"Old man, I want to claim my remaining wish." Zenitsu prayed.

"Make Muzan look like me and allow him to spend the rest of his life in peace as a human, in my stead over here."

"Granted. Do you want to return right now?" God's voice came to his mind.

"Yes, just let me vanish dramatically, but in silence." Zenitsu chuckled.

Muzan was confused to why would Zenitsu start praying out of a sudden, but then saw something that was beyond his wildest fantasies. His body changed and so did his clothes, he was the mirror image of the boy who stood before him.

Zenitsu stretched out his hand and Muzan took it shakily, he was overwhelmed, he was moved into tears. The two smiled at each other.

"Live well, Zenitsu Kuwajima." Zenitsu said as his body vanished into motes of light.

"I will." Muzan sobbed.

There were many questions in his mind but there was only one possible answer, Zenitsu was the angel God sent to help, the angel God sent him in the darkest of his days, even when he thought himself to be beyond salvation, God redeemed him.

A believer was born and the Sun rose from the eastern horizon. After centuries, he felt the warmth of the Sun, the warmth of a human heart, the warmth of kindness.

[A/N: Blast me some quirk ideas and a bad ass name for the BNHA arc. I will give a major shout out to the one who's idea I will be using.. You guys can also give some requests, if I can, I will keep them.. Try not to be too wild..]