We will discuss Muzan Kibutsuji’s backstory from Demon Slayer: Kimetsu No Yaiba in this blog post. He is the antagonist of Demon Slayer and is the strongest demon.

Muzan is cold-hearted, cruel, scare people, and is very smart.

He doesn’t see much value in any person he’s met, and he doesn’t see much value in the people who work for him, either. He rarely looks angry or happy.

Most of the time, even when he kills his own subordinates, he looks completely calm and uncaring. He only shows emotion when he is getting closer to his idea of perfection or when his subordinates do everything he says.

Muzan Kibutsuji Backstory | Muzan from Wiki
Muzan Kibutsuji Backstory | Muzan from Wiki

Here, we will see Muzan Kibutsuji’s backstory in Demon Slayer: Kimetsu no Yaiba. He is one of the main characters in Demon Slayer, and it would be interesting to read his backstory in the story.

Muzan Kibutsuji Backstory – As a Child

Muzan was born in Japan during the Heian era when life was hard because people were weak.

His heart stopped beating several times while he was in his mother’s womb, and when he was born, doctors said he was stillborn because he didn’t have a pulse or breathe.

When he was taken to be burned, he let out his first cries, which saved him from dying.

Muzan’s Weak Body

He had health problems when he was young, and that made him afraid of death.

Muzan was told when he was young that he had a disease that would kill him before he turned 20. Muzan’s doctor gave him a special test version of a medicine, but it didn’t seem to work.

Muzan Kibutsuji Backstory | Muzan as a human from Wiki
Muzan Kibutsuji Backstory | Muzan as a human from Wiki

Muzan killed his doctor because of how bad his illness was getting. He hated him because he couldn’t cure him with his medicines.

The Weird Side-Effect of Medicine

He didn’t realise that the medicine was working until after he killed the doctor. The medicine had helped him get a strong body. He knew that he needed to eat human flesh to stay alive, but this didn’t bother him.

On the other hand, his new, more severe problem was that he couldn’t walk in the sun because it burned him badly.

At that moment, he really felt bad that he had killed the doctor before he could have finished his treatment with the “Blue Spider Lily.”

Muzan Kibutsuji Backstory – Becoming a Demon

He looked for the flower all over the country but couldn’t find it. Because of this, Muzan started making more Demons and planned to send them all over the world.

He hoped that one of them would find a way to stop the sun or at least help him find the Blue Spider Lily. This obsession to be in the sun again consumes him for hundreds of years.

Muzan lived with five different women in his early years as a demon. But because he was a demon and lacked empathy and sensitivity, he verbally abused all five of his wives until they all killed themselves.

Muzan Finding Tamayo

Muzan found a sick little girl named Tamayo. She had a disease that could kill her.

She meets Muzan, and because she wants to see her children grow up, she lets him change her. As she got used to her new body, she killed her own family and another group of people by accident.

She couldn’t stop thinking about this choice, and it made her hate Muzan. But because Muzan was so powerful, she was not able to kill him.

Muzan made Tamayo his servant, and she had to follow him around.

Muzan Finding Kokushibo (Later, Upper Rank One)

Michikatsu Tsugikuni, a marked Demon Slayer who uses the Moon Breathing style, turns up later.

Michikatsu wanted to be stronger than his brother and hated that the fact that he was marked meant that he was going to die soon.

Muzan meeting Kokushibo
Muzan Kibutsuji Backstory | Muzan meeting Kokushibo

Muzan made a deal: he wanted to have a Demon who could use Breathing Styles, and in exchange, he would let him live forever and help him improve his skill. Michikatsu agreed, and Muzan gave him a lot of his blood. Three days later, Michikatsu was changed, and he took the name Kokushibo.

Muzan Kibutsuji Backstory – Meeting Yoriichi

Later, Muzan and Tamayo would meet Yoriichi Tsugikuni, Michikatsu’s younger twin brother and another Demon Slayer.

Yoriichi was Michikatsu’s younger twin brother.

Yoriichi could feel Muzan’s hatred and anger as soon as they met. He said that Muzan was like boiling magma. At the same time, Muzan didn’t see anything dangerous in Yoriichi and didn’t worry about his opponent.

Muzan was happy with Kokushibo being his subordinate, so he tried to kill Yoriichi without telling him.

He was able to avoid the blows, though, and figure out that Muzan had seven hearts and five brains that could move around his body.

Yoriichi Tsugikuni
Yoriichi Demon Slayer

Yoriichi put all of his forms into one attack, making his blade bright red. This let him cut through Muzan’s weaknesses and beat him.

Muzan vs Yoriichi

Muzan was shocked for the first time in his life. He couldn’t heal, so he sat in a pool of his own blood and glared angrily at Yoriichi, ignoring his question about what he thought life was worth. Yoriichi moved toward Muzan to kill him, but Muzan used what little power he still had to split his body in two with a powerful burst.

Even though Yoriichi was able to get rid of almost all of the pieces, the ones he missed let Muzan start over again.

Muzan was almost killed by Yoriichi during the fight.
Muzan was almost killed by Yoriichi during the fight.

He was deeply affected by this experience, and with Kokushibo’s help, he killed anyone who used Sun Breathing to try to stop another Demon Slayer who could kill him. They almost did it, and they almost got rid of Sun Breathing for good.

Muzan became very afraid of the Demon Slayers, who he thought was the real demon, so he never faced them directly again. Instead, he mostly got demons to do his bidding. Even after Yoriichi died, he was still afraid of him.

Muzan meeting Akaza

Muzan hears about a massacre in which 67 people were killed in a violent way. He went to the village before he met the person who did it, a boy named Hakuji, who was 18 years old.

He said he was upset because he thought a demon had done it instead of a person.

Muzan Kibutsuji Backstory | Muzan meeting Akaza
Muzan Kibutsuji Backstory | Muzan meeting Akaza

Hakuji tried to hurt him, but Muzan stopped him by putting his hand through Hakuji’s head. The Demon King told the young man about his plan to bring together twelve powerful demons and asked if he could handle the amount of blood he was given.

Hakuji was crushed by his loss and had nothing else to live for. He gave up and turned into the demon Akaza.

Muzan Kibutsuji Backstory – Making the Twelve Demon

Over time, Muzan was able to put together his group, which would later be known as the Twelve Kizuki. He changed many demons and let them join his group.

As a reward, he gave them a bigger share of his blood, which made them stronger.

The moons are divided into two groups of six, called the Upper Moons and the Lower Moons. The Upper Moons have been the same for hundreds of years.

On the other hand, the Lowers were always changing because the Demon Slayers were killing them, making him feel worse.

The Upper Moon Rank

Kokushibo, Akaza, an apathetic cult leader (Doma), a prolific and dangerous criminal (Hantengu), a dying murderer, a weak young boy, and a young man who he first ate but then changed were all Kizuki that he personally changed.

Upper Moon Ranks | by lincolndudes123
Upper Moon Ranks | by lincolndudes123

More demons, like a brother and sister(Daki and Gyutaro), a sick and murderous musician (Nakime), and a former Demon Slayer (Kaigaku), would join in the end.

Muzan Killing Kamado Family

Muzan was able to find the Kamado family, who were in charge of the Sun Breathing technique during the Taisho Era.

He attacked Tanjiro Kamado’s family while he was in town.

Kamado Family | Muzan Backstory
Kamado Family | Muzan Backstory

He then injected them with his blood, hoping to make a Demon that could stand up to the sun. But he was sad when his family died from the poison in his blood. This made him realise that making a Demon that could not be killed by the sun wasn’t so easy after all.

He left their house without knowing that Nezuko Kamado, who later became a Demon, was the only one left alive.

Final Thoughts – Muzan Kibutsuji Backstory

Muzan Kibutsuji started off in an era where the human survival rate was very low. Even though he was born weak, he got mutated by untested medicines. This incident gave rise to the demon era.

His ultimate goal was to stand up to the sun. He sacrificed thousands of people for this one goal, made hundreds of demons and turned everything upside down.

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About the Author

Logan Rane

Hey, I'm Logan, and I love anime and manga. I could talk about them all day, write about them non-stop, and watch them around the clock. I've watched hundreds of animes and read thousands of mangas at this point in my life - so you could say I'm pretty deep into it all.

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