Muzan Kibutsuji is, in my humble opinion, one of the best villains to come out of anime in recent years. While he is shown very scarcely in the anime, the few scenes where he is present display his exceptional intelligence, charming charisma, and capacity for violence. However, the real question here is why. Why is Muzan the way he is and what drives him to commit the acts that he does? That is what I will be attempting to answer.
While I would love to say that this will be spoiler free for those who have not read the manga, it would be impossible to do this without spoilers, hence the spoiler warning in the title.
First, some backstory. Muzan was born as a sickly human child who had been told that he would not live to the age of twenty years old. Nothing could cure him. The medicines of the time did nothing to aid him in his suffering and this only served to infuriate the boy who was resigned to a fate he had no control over.
This all came to a head when a doctor came to him with an experimental treatment. Muzan took it and, not feeling himself get better, he killed the doctor outright (I’m fairly certain that this doctor was his first ever act of murder). Only after the fact did little Muzan realize that the medicine had worked, curing him of his disease, but also making him powerful and immortal. But this blessing came with a curse. He was given one lingering weakness. Muzan could not walk in the sunlight, otherwise he would die.
Fast forward a lot and we get to the present day. Muzan has been running around, creating demons and studying up on his own physiology in order to figure out a way to not be destroyed by sunlight. He himself feels that, if he were to overcome this weakness, he would be the perfect being.
Okay, let’s unpack this.
First and foremost, let me make an assumption that I think other people have probably already made because, not gonna lie, I am a little bit slow. Kimetsu no Yaiba, at its core, is the story of humanity. Particularly, the story of Human Weakness. On one side, we have the Demon Slayers. The Demon Slayers have overcome their very human circumstances, regardless of how negative and how traumatizing they were, and strive to achieve greatness by exceeding their human limitations and weakness. On the other side, we have the Demons. Demons (who were once human) experience the same traumatizing human circumstances that the Demon Slayers faced, but, instead of attempting to overcome those circumstances, they instead decided to cast off their humanity, and thus their human weakness, to become something that they perceive as better than human.
With that in mind, let’s continue talking about Muzan. Muzan doesn’t simply dislike human weakness, he detests it. He has a burning hatred for weakness and abhors anything that suggests that he is in any way weak. It is his own belief, based on what I’ve seen thus far, that to be a “perfect” being, one must overcome any and all weaknesses. And, seeing as he has already done away with his human weaknesses, he concerns himself with his demonic weakness, sunlight. This is evidenced by a quote from the demon himself where he says, “I am a perfect creature that is infinitely close to perfection.” Muzan believes that he is perfect, but has not yet achieved perfection due to his singular weakness. But he does not only hate seeing any weakness in himself, he hates it when he sees it in others as well.
This is shown in the scene where he kills the Lower Moons. “Why is it that you demons in the Lower Ranks are so utterly weak?” He (She?) asks. Muzan actively hates the weakness shown by the Lower Moons and slaughters most of them for the crime of being so weak. The only one he leaves alive is Enmu, and this simple act of mercy was due solely to the fact that he stroked Muzan’s ego in just the right way to receive some mercy.
There are other examples of Muzan’s hatred for weakness in the manga, but I’m trying to keep the number of spoilers to a minimum for the sake of those who have only watched the anime.
With all that said, the answer to the question of what drives Muzan to behave the way he does is simple enough to understand I think. The answer is fear. More specifically, I think that it is the fear of weakness. Because he grew up the way he did, sickly and destined to die, this created both fear and anger within him. He fears weakness because weakness ultimately leads to death, and he hates weakness for that exact same reason. He seeks to be perfect because perfection would mean that he has overcome any and all weaknesses. He seeks to eliminate the Demon Slayers because the only thing that would be able to kill him once he achieves his goal of being able to walk in the sunlight is the Crimson Nichirin Blades that they have the potential to wield.
And that, dear reader is my analysis of Muzan Kibutsuji. If you read this article but have not yet watched the show, you can watch it here. If you have watched the show but need to get caught up on the manga, read it here.
Thank you for reading!