Suguru Geto (夏 (げ) 油 (とう) 傑 (すぐる)  Getō Suguru?) is an antagonist in both the Jujutsu Kaisen series and its prequel Jujutsu Kaisen 0: Jujutsu High. He was originally a student of Masamichi Yaga's alongside Satoru Gojo and Shoko Ieiri at Tokyo Jujutsu High. His experiences as a jujutsu sorcerer bred a deep hatred for non-sorcerers, leading to an incident where Suguru massacred over a hundred civilians in a single night.

Suguru was a much more kind and proper young man back then, especially compared to Satoru. He understood the importance of manners and carrying himself with dignity at a jujutsu sorcerer. Satoru had far too rude of an attitude in his opinion.[11] Despite disagreeing from time to time, Suguru and Satoru were still best friends. They encouraged each other to be the strongest and were confident they could accomplish anything as long as they had each other.[12]

However, following Riko Amanai's death, things began to change.

Suguru Geto hated non-sorcerers, usually referring to them as "monkeys". He felt sorcerers are the superior race and humanity's next stage of evolution. He was smug and extremely condescending towards normal humans, using fake personas to lure in vulnerable people who were cursed. Suguru found non-sorcerers disgusting enough to spray himself in order to disinfect the "monkey stench". He believed monkeys only have two roles in association with him, money-collecting monkeys and curse-collecting monkeys. If they weren't fulfilling their roles, Suguru would gladly allow curses to kill them without any remorse.