According to series creator Gege Akutami from the official "Jujutsu Kaisen" Fanbook, even before he technically became a Cursed Spirit, Ryomen Sukuna already had the title of the "King of Curses," and as a human was more of a "natural calamity" (via Comic Book.com). That's terrifying, considering what Sukuna has done so far in the series as a Curse. His power is made clear during the anime's second episode, when Satoru Gojo explains to Yuji that Sukuna is such a powerful Curse that no one can destroy any of his 20 fingers that contain fragments of his power. Gojo, who is considered to be the most powerful Jujutsu Sorcerer in the series, then tries to destroy one of Sukuna's fingers. Instead, the sorcerer manages only to damage the wall.
When Sukuna gets the chance to fight, the difference in power between him and other Curses is shown as he handles most battles easily. In episode five, he effortlessly kills a Finger Bearer that was considered a Special Grade Curse. In the Shibuya Incident Arc (via Viz) of the "Jujutsu Kaisen" Manga, Sukuna fights and beats Special Grade Curse Jogo with little problem and defeats General Mahoraga, which is considered to be one of the most powerful Shikigami. His battles in the recent arc also leave much of Shibuya in ruins. And, in terms of popularity, Sukuna won Cunrchyroll's Best Antagonist Award from their 2021 Anime Awards. As far as the villain is concerned, no other Curse comes close to him.
