In Demon Slayer: Kimetsu no Yaiba, Muzan Kibutsuji — the immortal Demon King and the source of all tragedy — is the embodiment of absolute power. And yet, there is one person who haunted him to the core: Yoriichi Tsugikuni, the strongest Demon Slayer in history. Despite Muzan’s regenerative abilities and supposed immortality, why did Yoriichi instill such deep fear in him? Let’s explore the roots of this obsession.
Who Was Yoriichi Tsugikuni?
Yoriichi was a legendary swordsman from the Sengoku era who created Sun Breathing — the original technique from which all other Breathing Styles descended. Born with divine talent and strength far beyond any human, he was the only person who ever brought Muzan to the brink of death. Their encounter (Chapters 186–187) left an unhealable scar — both physical and psychological — on Muzan.
Why Muzan Feared Yoriichi
Overwhelming Power
- Sun Breathing: Yoriichi’s Sun Breathing was the only technique capable of causing lasting damage to demons — especially to Muzan. His use of the “Thirteenth Form” combined all previous Sun Breathing forms into one relentless assault, slicing Muzan into over 1,500 pieces in mere seconds.
- Unmatched Speed and Precision: Yoriichi was so fast that Muzan couldn’t react in time — despite his rapid regeneration. One swing from Yoriichi’s blade nearly ended Muzan permanently.
The Defining Battle
- Muzan Was Crushed: During their only battle (Chapters 186–187), Muzan — typically arrogant in his immortality — was completely overwhelmed. He barely escaped by forcibly splitting his body into fragments.
- An Eternal Scar: Yoriichi left behind a wound that never healed. This mark served as a lifelong reminder of Muzan’s failure and vulnerability.
The Transparent World
- Perfect Perception: Yoriichi was born with the ability to see the “Transparent World,” allowing him to detect every muscle movement and weak point of his enemy — similar to the Six Eyes in Jujutsu Kaisen. This made Muzan’s regeneration useless — every counter was anticipated.
- The First Demon Slayer Mark: Yoriichi was the first to awaken the Demon Slayer Mark, enhancing his speed and power to a near-divine level. Muzan had no answer to this.
Why Fear an “Immortal”? Because Yoriichi Nearly Killed Him
The Brush with Death
- Muzan’s Limits Exposed: For the first time, Muzan faced someone who could permanently destroy him. He later admitted that had Yoriichi continued the pursuit, he would have died (Chapter 187).
- A Shattered Ego: Yoriichi destroyed Muzan’s confidence. Muzan believed himself invincible, but Yoriichi showed him fear — a human emotion he thought he had outgrown.
A Lingering Obsession
- Hunting Sun Breathers: After the battle, Muzan obsessively hunted and exterminated every Sun Breathing user or anyone bearing a Demon Slayer Mark (Chapter 192). His fear was not of Yoriichi alone, but of his legacy living on.
- The Kamado Tragedy: Muzan slaughtered Tanjiro’s family simply because he suspected a connection to Sun Breathing — showing how deep his paranoia ran.
- Memory That Wouldn’t Fade: Even after Yoriichi died of old age, his image haunted Muzan. He never dared to directly face another warrior of equal potential again.
How Yoriichi Compares to Muzan’s Other Foes
| Opponent | Power | Impact on Muzan |
|---|---|---|
| Yoriichi | Sun Breathing, Demon Slayer Mark | Nearly killed him, left permanent fear |
| Tanjiro | Sun/Water Breathing | Defeated Muzan with help |
| Tamayo | Demon-altering drugs | Weakened Muzan indirectly |
| The Hashira | Traditional Breathing Styles | Slowed Muzan down, not fatal |
The Symbolism Behind Muzan’s Fear
- A Glimpse of Humanity: Muzan’s fear of Yoriichi reveals he’s not entirely emotionless. He fears death, failure, and loss of control — very human vulnerabilities hidden beneath a monstrous form.
- Justice Made Flesh: Yoriichi represented absolute justice and discipline — the complete opposite of Muzan’s chaos and selfishness. He was not just a swordsman, but an eternal nightmare Muzan could never silence.
Conclusion
Muzan feared Yoriichi not just because of his overwhelming strength — Sun Breathing, divine speed, and perfect awareness — but because Yoriichi was the only person to bring him to the edge of death. Yoriichi shattered Muzan’s illusion of immortality, and that fear lived on for centuries.
His obsession with erasing Yoriichi’s legacy led to his downfall, as Tanjiro — the spiritual successor to Yoriichi — ultimately defeated him. Yoriichi wasn’t just a threat; he was Muzan’s eternal nightmare. Will the shadow of Yoriichi’s will continue to shape the Demon Slayer world? Keep watching — his presence lingers still.
