What If

Junpei might have become Yuji's friend and a fellow student at Jujutsu High, but Mahito cuts that future short, sacrificing the boy to advance his own scheme and make contact with Sukuna. Watching his potential friend die at the cursed spirit's hands, Yuji is consumed by a rage he has never felt before, and in that fury he taps a power he did not know he possessed.

Mahito approaches as Yuji hesitates, briefly mistaking the curse for a human, before Mahito reveals himself and pins Yuji with a deformed arm, greeting him as Sukuna's vessel. Yuji begs Junpei to flee, and Junpei begins to defend Mahito until memories of the curse's cruel experiments make him grasp the truth too late. Whispering that Junpei was no smarter than the people he looked down on, Mahito uses Idle Transfiguration to warp the boy's body into a monster and forces him to attack. Yuji pleads with Sukuna to heal Junpei, but the King of Curses refuses and mockingly notes that Yuji forgot their binding vow, prompting Mahito to question whether such a vow ever existed. The two laugh at Yuji's anguish. Junpei dies asking why this had to happen, and Mahito jokes that he transfigured him too aggressively. Enraged, Yuji lands a punch that hurls Mahito into the stairs, and the curse's bleeding nose reveals the blow connected with his soul. Mahito realizes that sharing a body with Sukuna has taught Yuji to perceive the soul. Resolved to kill for the first time, Yuji declares he will destroy Mahito, who corrects him that sorcerers say exorcise.

This is the twenty-seventh chapter, collected in Volume 4 within the Vs. Mahito Arc, with the Japanese title Moshimo. It is the first chapter whose Japanese title is written entirely in hiragana without a single kanji. The featured technique is Mahito's Idle Transfiguration, and the chapter opens the battle between Yuji and Mahito, adapting into the anime's twelfth episode.