Demon Slayer: Why is Muzan so evil? Villain’s goals and motivations, explained

Muzan is the king of all demons in Demon Slayer. He is the original demon - and the progenitor of all other demons in turn. He’s centuries old, and holds little regard for humans as anything more than sustenance and potential slaves. Muzan is undeniably, inhumanly evil. Which may leave many fans to ask, why?

Truthfully, Muzan’s been twisted by his immortality and his origin didn’t help matters. Born with a weak heart and constitution, he was diagnosed with a disease that would kill him by the age of twenty. However, he was saved by a medicine that transformed him into the first demon, which began Muzan down a path driven by the power he wielded - molding him into the monster we know.

Disclaimer: This article contains spoilers for Demon Slayer.

---

Demon Slayer: Muzan sees humans as infra dig

Muzan's driven mad by the sheer power being a demon grants him. (Image via Ufotable)

Muzan is pure evil, as many demons are in Demon Slayer. It seems most of this evil is founded out of believing himself to be strictly superior and above human existence. As Muzan views humans as simple sustenance to be consumed, he usually treats them as utterly disposable - best displayed in his acts of brutality towards a drunk man and his family for offhandedly insulting him.

As mentioned, when he was still human, Muzan grew up as frail and weak. He turned to an experimental treatment for help. While the treatment worked, transforming him into a demon, he killed the doctor when he thought it didn’t, meaning the treatment could never be truly finished.

Either way, it made him superhuman - for the first time in his life, Muzan had true power in his grasp. No longer would he be the weakling.

He’s utterly self-obsessed, to the degree only someone alive for over a millennium can be. He had five wives in his early years of being a demon, but drove all of them to suicide with his lack of empathy.

He transformed those like Doctor Tamayo and Michikatsu Tsugikuni into the first demons, exploiting their emotions to grow his army. But one man would make Muzan feel fear after years of confidence.

---

Muzan fears the Sun-Breathers

Muzan can't stand up to the Sun-Breathing technique. (Image via Koyoharu Gotouge)

The Sun-Breathing technique was utilized by the legendary Demon Slayer Yoriichi Tsugikuni, and was the bane of Muzan. Yoriichi was nearly successful in slaying Muzan, scarring him deeply with his sunlight-divining power. Muzan only escaped by dividing himself into small pieces and fleeing.

Showing his cowardice, Muzan resolved to hunt down all who used this technique to fight - particularly the Kamado clan. However, the Kamados simply used it as a ritual dance, not as a demon-slaying technique. Muzan killed them regardless, but made his greatest mistake in leaving one alive: Tanjiro Kamado.

This would come back to bite Muzan, as the boy sought vengeance for his family and his demon-cursed sister, utilizing the sun-breathing technique perfected by his ancestor once again against Muzan, alongside that of water breathing.

With the combined force of Tanjiro and other brave Demon Slayers, Muzan would ultimately fall - something that would've never happened had he left the Kamados alone.

Muzan's evil in Demon Slayer was ultimately driven by spite for his once-weak human form and against the humans he now viewed as beneath him. Due to his immortality, he became narcissistic, viewing himself as far above human concerns - yet Muzan was still dominated by basic emotions like fear. He feared immortality would come to an end, that would lead him to his own downfall.