A curse can be destroyed, but only by another curse.

Enter Yūji Itadori, a seemingly normal high school boy that possesses amazing physical abilities. His close friend falls victim to an attack by a “curse” and the only way to save him is to consume a special-grade curse “double-sided inn’s finger” which puts a curse in his soul. I soon learns he must train and find and devour all of the demon’s fingers to save himself.

From IMDb:
Yuji Itadori, a kind-hearted teenager, joins his school’s Occult Club for fun, but discovers that its members are actual sorcerers who can manipulate the energy between beings for their own use. He hears about a cursed talisman – the finger of Sukuna, a demon – and its being targeted by other cursed beings. Yuji eats the finger to protect his friends, and ends up becoming Sukuna’s host. However, Yuji discovers that he has inherited magic and is able to control this power without interference from Sukuna. He joins the Tokyo Metropolitan Magic Technical College to consumes all of Sukuna’s fingers, which will enable a full exorcism to take place that will free him.