Muzan is a demon who lives under the law of the fittest. However, what distinguishes him from other villains like, for example, Akaza, is that he does not place any importance on qualities such as strength or honor. Muzan murders indiscriminately and only allows to live the demons that can be useful to him. The part that fascinates me the most about Muzan is that, in a swordsman manga like Kimetsu no Yaiba so inspired by samurai culture, he doesn't have any value like you would expect from the main antagonist. He is, in spirit, a very pathetic person, since he has the cool to end any life in a selfless manner, but he is too afraid of losing his own. He hates sunlight, not only because it is his only existing weakness, but also because it reminds him how weak he really is.
Besides the psychological factor, Muzan is an excellent villain in his presentation, in my opinion. At first, I thought that his only appearance was going to be the one seen in the first episodes, in which he is a refined and good-looking man in an elegant suit and hat. This design already seemed very good to me at the outset, but it only got better as the series progressed. Later, Muzan takes on the appearance of a beautiful woman, which makes him incredibly terrifying, due to what it implies. It would be enough for him to modify his voice to deceive and seduce any man, when in reality it is a male demon who could kill him whenever he wanted. This unexpected and ambiguous factor increases in intensity when Muzan takes on the appearance of a child and pretends to be part of a common family. A child, that anyone would see on the street and would get an innocent smile, turns out to be the King of Demons. Finally, in the final arc of the manga, Muzan reveals what is possibly his true appearance, or at least the closest thing to it. His hair grows and turns white, and it is possible to distinguish demonic mouths with sharp teeth along his body. This becomes even scarier when you discover that his internal organs are uniquely managed within his body, plus they are constantly moving.
In conclusion, Muzan Kibutsuji is a very interesting villain who offers more than the general public can get to see. As a Kimetsu no Yaiba fan myself, it took me a while to realize how much I actually like this character. I think he works as a perfect enemy for the noble souls that are Yoriichi and Tanjiro. What do you think?
