Chapter 212

Megumi's plan to save Tsumiki collapses entirely once an incarnated sorcerer confesses she has been posing as his sister all along. Before his allies can mount any real response, Sukuna seizes the opening to make his move at last.

A flashback shows Megumi visiting the newly woken Tsumiki, promising her that the Culling Game and Gojo would be handled by him and the others, while she answered with an oddly devious smile. Another recalls Yuji coming to terms with his place in the jujutsu world, thankful to Megumi and Gojo for handing him a purpose. In the present, the false Tsumiki enacts a rule permitting free crossing between colony borders, then sneers and mockingly calls herself Megumi's big sister. She explains that a cursed object absorbs its vessel's memories and modern knowledge once it takes on flesh, which is how she wore Tsumiki's identity. Realizing he wrongly pegged her as an awakened player, Megumi listens as she gives her name: Yorozu, an ancient sorcerer reincarnated inside Tsumiki's body, who admits she gladly took the offered points so she could pick her battlefield and face Sukuna.

As Yorozu departs and Yuji moves to chase her down with Hana, a mouth opens on Yuji's face and utters Enchain, the trigger of a binding vow Sukuna had pressed onto him as he died, surrendering Yuji's body to Sukuna for one whole minute. Sukuna drops Hana without harming her, honoring the vow's conditions, then rips off one of his fingers and pauses to confirm the vow holds, proving Yuji carelessly omitted himself from the list of people Sukuna was barred from hurting. As Megumi reaches for Mahoraga, Sukuna's speed breaks up the hand signs, and he makes Megumi swallow the severed pinky, incarnating into him. Leaving Yuji's body completely, Sukuna takes hold of Megumi and reminds Yuji of his earlier vow that something interesting was coming.

This Culling Game arc chapter, collected in Volume 24, introduces Yorozu and lays bare the full scope of the binding vow Sukuna fixed on Yuji. It marks Sukuna's leap from Yuji into Megumi's body, a turning point for the series. Trivia points out that the two consecutive chapter titles, Ripen and Fester, read as homophones despite being spelled with different kanji.