Kibutsuji Muzan truly deserves his role as the main villain of Demon Slayer/Kimetsu no Yaiba. Few characters fit this role better than him, as his crimes are brutal and driven by selfishness. Even more terrifying, he constantly tries to justify his actions.
From mass murder, destruction, cannibalism, terrorizing others to abusing children, Muzan’s list of sins is so long that almost no lawyer could defend him. Here are the five most heinous acts he commits throughout the series.
5. Treating the Twelve Kizuki as disposable tools
Even the strongest demons under Muzan’s command are nothing more than pawns to him. He does not hesitate to eliminate any subordinate who disappoints him.
Thanks to a deadly curse in his blood, Muzan can control the Twelve Kizuki and punish or kill any demon who fails to meet his demands.
To Muzan, the lives of those who serve him hold almost no value. However, since eliminating these demons sometimes benefits the protagonists, this crime is often viewed as less severe than others. That’s why it ranks fifth.
4. Stripping Hakuji of his humanity
What Muzan did to Hakuji is truly despicable. Hakuji was Akaza’s human identity. After losing Koyuki and Keizo, he fell into despair. Muzan appeared, fueling his hatred and rage, then turned him into a demon.
This process caused Hakuji to lose all memories of his human life and become Akaza, one of the most ruthless demons in Demon Slayer.
Since viewers first met Akaza without knowing Hakuji’s tragic past, this crime ranks fourth.
3. Turning Tamayo into a demon
Unlike Akaza, Tamayo had to live with the consequences of Muzan’s actions for hundreds of years. Muzan not only turned her into a demon but also let her keep her memories. This meant Tamayo had to endure the curse of immortality and an unending thirst for blood.
Although she eventually escaped Muzan’s control, Tamayo suffered centuries of pain and the aftermath of his decision.
For this reason, turning Tamayo into a demon deserves a spot in the top three worst crimes committed by Muzan.
2. Murdering the Kamado family
Imagine leaving your home for a short time and returning to find nearly all your loved ones brutally murdered. This is the tragedy the Kamado family faced.
In just one night, Muzan slaughtered almost the entire Kamado family. He didn’t stop there, he also turned Nezuko into a demon. In a single event, Muzan caused two devastating tragedies: the murder of Tanjiro’s family and the transformation of his sister into a demon.
The scale and consequences of this act sparked the entire Demon Slayer story, earning it second place on the list.
1. Pursuing immortality at humanity’s expense
Most of Muzan’s cruel actions ultimately aim at one goal: achieving absolute immortality.
While humans fear death, Muzan’s obsession with overcoming it turned him into someone willing to do anything to reach his goal. He experimented on humans, created countless demons, and manipulated or sacrificed anyone who could help him overcome his vulnerability to sunlight.
To Muzan, other people’s lives are merely tools to serve his ambition. This obsession with immortality ranks as his most unforgivable crime.