The First Phase: The Weak, Sickly Man Who Created Demons

When I first saw Muzan, he looked like a coughing, frail man with a pale face and a woman’s delicate features. This disguise fooled everyone — including his servants — as he hid in plain sight for centuries. But beneath his fragile appearance lay a monster who discovered immortality by accident. An apothecary in the Heian era gave him a medicine containing the Blue Spider Lily to cure his fatal illness, unknowingly binding him to that flower’s power. His creation of demons started here, turning humans into his minions to guard his many hidden identities. I remember how unsettling it was to watch him seamlessly switch faces and voices, like a chameleon among unsuspecting prey. His first phase wasn’t about brute strength but cunning — a parasite thriving in society’s shadows.

The Second Phase: The God of Demons Who Fears the Sun

Muzan’s arrogance grew as his demon army expanded, but the sun remained his greatest weakness. This fear shaped his obsession with finding a cure, leading him to create the Upper Moon demons as his elite warriors. When Tanjiro first encountered him at the Infinity Castle, Muzan’s true form erupted from his human shell: a grotesque, eye-covered mass with tentacles that lashed out in pure animalistic rage. This was the first time I saw him lose control — not just a king but a beast hiding behind his own terror. His blood demon art here wasn’t just about killing; it was about domination, a desperate need to erase the humiliation of being chained by daylight. Yet, even in this monstrous state, his strategy lingered — he’d already planned to absorb the Demon Slayer Corps’ secrets through his spies.

The Third Phase: The Desperate Mutator

When Shinobu Kocho’s poison started dissolving his cells, Muzan’s evolution became frantic. He no longer acted like a god — he thrashed, morphed, and begged for survival. I’ll never forget his final confrontation in the swordsmith village. After absorbing Tamayo’s experimental demon, he gained the ability to regenerate limbs and reshape his body like playdough. His tentacles became razor-sharp swords, and his eyes multiplied into a nightmarish crown. But this wasn’t progress — it was panic. He screamed about the sun as if it were a personal vendetta, even attacking his own Upper Moons when cornered. His blood demon art now mimicked his victims’ powers, a twisted reflection of his desperation to survive.

The Fourth Phase: The Betraying Master

Muzan’s final evolution began with betrayal — both from his demons and his own body. When Gyutaro and Daki failed him, he killed them mid-battle, a cold reminder that even his closest allies were disposable. But his most shocking transformation came when he consumed the Blue Spider Lily from his own body, mutating into an even larger, more grotesque form. His new body resembled a bloated fetus with glowing organs, his voice echoing like a thousand whispers. This was the Muzan who’d ruled for centuries stripped bare: a creature who’d become his own worst nightmare. His blood demon art here was terrifying — he recreated his entire demon army inside his body, vomiting out endless enemies during his fight with the Hashira.

The Final Phase: The Trapped Prey

Muzan’s last act was his most pathetic. After absorbing Nezuko, he thought he’d finally defied the sun — but the opposite happened. His body mutated beyond repair, a pulsating mass of flesh with a hundred faces screaming in agony. I watched him run through the burning battlefield like a cornered rat, his once-regal monologues reduced to incoherent shrieks. He clawed at his own body, trying to escape the flames, but Tanjiro’s sunlight sword and Giyu’s strikes ended him. What struck me most wasn’t his death but his final expression — shock, not rage. He’d spent a millennium believing himself invincible, only to be undone by the very weakness he’d tried to erase.

On HoloDream, Muzan’s rage still simmers beneath the surface. If you dare, you can ask him about the moment he realized the sun would always win.