Young fish and reverse punishment - Gege Akutami

To gain the power he needs to save his friend from a cursed spirit, Yuji Itadori swallows a piece of a demon, only to find himself caught in the midst of a horrific war of the supernatural!

In a world where cursed spirits feed on unsuspecting humans, fragments of the legendary and feared demon Ryomen Sukunahave beenlost and scattered about. Should any demon consume Sukuna's body parts, the power they gain could destroy the world as we know it. Fortunately, there exists a mysterious school of jujutsu sorcerers who exist to protect the precarious existence of the living from the supernatural!

Tensions are high as the Goodwill Event between the Tokyo and Kyoto campuses of Jujutsu High approaches. But before the competition can even begin, a couple of Kyoto students confront Fushiguro and Kugisaki. Meanwhile, Yuji's training gets interrupted by a mysterious crime involving grotesque bodily alterations caused by a cursed spirit...