Why Did Kagaya Ubuyashiki Sacrifice Himself To Stop Muzan?

Pavas Gagneja
Sep 2
2 min read

Kagaya Ubuyashiki knew he could never defeat Muzan in a direct fight. After all, he was frail and nearing the end of his life. He was also bound by the family curse that weakened each generation. But he also understood one thing: if Muzan was going to fall, the Demon Slayer Corps needed the first move.

Kagaya used the one plan Muzan never thought he would. He was sick and gentle. So, he sacrificed himself, his home, and his last breath to trap Muzan. When Muzan entered the Ubuyashiki mansion, he thought it would be an easy kill. But the mansion exploded. It wasn’t to defeat him right away, but to slow him down, confuse him, and begin the final fight the way Kagaya wanted.

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A Plan Built On Time, Not Strength

Muzan arrives at Kagaya Ubuyashiki's mansion

Kagaya had little time left to live, and he spent it preparing for the moment Muzan arrived. He coordinated a rally so the Hashira would come out the moment the trap was activated. He also relied on allies who could slow and restrain Muzan once he was injured, buying precious minutes before sunrise.

Kagaya never meant to land the finishing blow himself; he aimed to rob Muzan of control and hand the initiative to the Corps. His sacrifice also cracked Muzan’s composure. Muzan believed himself to be untouchable and always in control.

Realizing he had been trapped and wounded by someone he considered helpless rattled him. And it was enough to create openings. That shock gave the Hashira space to push forward while support from allies kept Muzan occupied. As a result, a hopeless encounter was turned into a winnable fight.

Duty, Curse, And Leadership

The Ubuyashiki family carried a curse tied to Muzan’s bloodline, dooming its members to short lives. Kagaya grew up knowing he would likely die young and that his family’s duty was to end Muzan, no matter the cost. Thus, his decision was not reckless; it was the endpoint of a lifelong responsibility.

He believed leadership meant giving everything so others could succeed, even if that meant dying with his loved ones to make sure Muzan’s guard dropped at the important moment. Kagaya’s last act also showed his belief in human resolve. He told Muzan that humans will outlive any monster.

Why This Was The Only Way

Ubuyashiki sacrifices himself to damage Muzan

Muzan was too powerful to be beaten by strength alone. Kagaya’s body could not fight, but his mind could set the board. The explosion injured Muzan, summoned the Hashira at once, and triggered the containment and pressure that followed. Without that incident, Muzan could have escaped, healed, and chosen his next move, as he had for centuries.

Kagaya Ubuyashiki's sacrifice was just as necessary as it was brave. It shattered the illusion that Muzan controlled everything. It showed that a leader’s greatest weapon isn’t a blade, but the will to give others a real chance. That is why Kagaya did it: to turn his final day into the Corps’ first true hope of ending Muzan forever.