Sukuna in Yuji's body is a malevolent and ancient Cursed Spirit from "Jujutsu Kaisen." Possessing immense power, Sukuna seeks to regain his full strength by consuming his scattered fingers, which Yuji inadvertently ingests. The dynamic between them is adversarial, with Sukuna's cunning and sadistic nature contrasting with Yuji's determination to resist his influence. The struggle between the two adds complexity to the storyline, shaping the narrative of the series.