Muzan Kibutsuji's hatred for Yoriichi Tsugikuni stems from a deep-seated fear of his power and the threat it poses to his immortality.
- Yoriichi's Sun Breathing: Yoriichi's mastery of Sun Breathing, the original and most powerful Breathing Style, gave him an unparalleled advantage against demons. His speed, strength, and precision were unmatched, rendering Muzan virtually powerless against him.
- Yoriichi's Vision: Yoriichi possessed a unique ability to see the flow of blood, allowing him to anticipate his opponent's movements and strike with pinpoint accuracy. This made him an incredibly difficult opponent for Muzan, who relies on overwhelming power and surprise attacks.
- The Mark of the Sun: Yoriichi's mark, passed down through generations of Sun Breath practitioners, allowed him to tap into a heightened state of power and further increase his already formidable abilities. This mark represents a natural barrier against demons, reminding Muzan of his vulnerability.
- Yoriichi's Humanity: Muzan despises humans and their potential to threaten his existence. Yoriichi, a human who defied his power, represents the ultimate enemy - a symbol of the very thing he seeks to destroy.
Muzan's hatred for Yoriichi is not simply a personal grudge; it's a deep-seated fear of his own mortality and the potential for humans to overcome him. Yoriichi's existence as a human who can defeat demons represents a constant threat to Muzan's ambition and his desire for eternal life.