Yuji Itadori is the protagonist of Jujutsu Kaisen and a character that the fans were always interested in seeing the progression of. Just like the vast majority of the shonen protagonists, Yuji was bestowed with a power right at the beginning of the story, and in his case, it was Ryomen Sukuna. That said, Sukuna was more of a burden for Yuji than anything. Having his own goals to fulfill, Sukuna had no problems existing inside Yuji and biding his time, but doing so eventually bestowed Yuji with some great abilities as well, most of which bore fruits in the Shinjuku Showdown Arc of the story.