War Devil arc

This storyline is the sixth and concluding portion of the Academy Saga, and counting from the very start of Chainsaw Man it ranks as the fourteenth arc overall. Picking up once the Aging Devil has been put down, it gathers nearly every dangling thread of the second part: Yoru's true nature, the impending descent of the Death Devil, and the question of whether Denji can carve out an ordinary life amid the chaos. Several new figures enter the story here, among them the genuine Famine Devil, the Fire Devil, and the Locust Devil.

Yoshida discloses that Public Safety now holds Katana Man, Haruka, Nobana, and Seigi captive, and presses Yoru to forge Denji into a weapon for humanity's defense. Denji at last grasps why his ordinary life was stolen from him as Yoru, revealed as the War Devil sharing Asa's body, drags him off to enjoy herself across a collapsing Tokyo. Atop a rooftop over potstickers, she lays out what awaits once the Death Devil arrives, and strikes a bargain: best the Death Devil and she will sleep with him, fail and she will turn him into a weapon aimed at her eldest sister. Meanwhile a jittery transfer student at Fourth East High proclaims she will save humanity through death, only for the Fake Chainsaw Man to cut her down repeatedly. She names herself as the Famine Devil, but the being acting under the Fami alias is exposed as the real Death Devil, who subdues both combatants with the Falling Devil's aid and resurrects them as brainwashed pawns. A sprawling battle erupts as Denji, Asa, and Yoru clash with the Fake Chainsaw Man and the Falling Devil. The doppelganger is revealed as the elder brother of a student Denji once failed to save during the Cockroach Devil fight, and the Fire Devil emerges from within him to warn Denji against repeating that mistake. After defeating the Falling Devil and absorbing it into a new outfit, Yoru remembers nuclear weapons amid news of war between the Soviets and Americans, her power swelling enormously.

The Death Devil reveals her plan to Denji: Yoru intends to erase her and ignite an endless World War where undying humans suffer forever. Yoshida is killed by Barem Bridge's explosive assault, prompting Pochita to seize Denji's body and devour Barem. Yoru then descends from Hell to wage war for ownership of the world, and a savage duel follows. After Pochita consumes the Death Devil and erases mortality itself, Denji fully merges with Pochita to overpower Yoru, sparing her only when she swerves to avoid killing a dove tied to Asa's guilt. Lending Yoru his blood, Denji forms a truce, but both are swallowed by descending devils. In a final mindscape, Pochita tears out his own heart and devours himself, wiping his existence away to birth a reality where Chainsaw Man never was. Denji wakes in his old shack, is saved anew by Power, and is recruited into Nayuta's Public Safety, glimpsing a now-ordinary Asa at Fourth East High before heading home.