Um, Actually

In Jujutsu Kaisen, we follow our high school protagonist Itadori Yuji, who are friends with the occult club. After the club unsealed the rotten finger belonging to the King of Curses, Sukuna, other Curses are attracted to it and swarm the school. Yuji swallows the finger to gain its power and saved his friend. Despite being required to exorcise Yuji immediately, Gojo noticed that Yuji has control over his body and thus gave an alternative proposal: postpone Yuji's death sentence until he consumes all 10 of Sukuna's fingers so that Sukuna can finally be eliminated together with Yuji. Thus begins the story of Yuji training under Gojo with the rest of his school mates while he participates in exorcising other Curses.