Sukuna Ryoumen

Known as the undisputed King of Curses (呪いの王), Sukuna, according to legend, was a demon (though in truth was a human Sorcerer) during the prime era of Sorcery 1000 years ago, and Sorcerers gave their all to defeat him. After his death, his corpse was unable to be fully destroyed, and thenceforth his remains of 20 fingers, preserved in grave wax, traversed the ages as Cursed Objects. In the present, Sukuna was incarnated into Yuuji Itadori due to the latter eating one of his cursed fingers, which contain his fragmented power.

Sukuna has now forced Megumi Fushiguro into becoming his vessel, replacing Yuuji Itadori. He gains the Ten Shadows Technique through this.

Sukuna learned to unleash a slash that bisects the world itself after using Mahoraga's second adaptation against the Limitless as a model. He uses this same slash to bisect Satoru Gojou, concluding the battle of the strongest.
(Source: Wikipedia)