Urumi Kanzaki stands as the antithesis to the "dumb blonde" stereotype, being a prodigy with an IQ surpassing 200. She is also heterochromatic, having one brown eye and one blue eye. Despite her brilliance, she harbors deep psychological disturbances, particularly a strong disdain for teachers. Her genius manifests through unconventional acts like setting off time bombs (actually firecrackers in disposable boxes) and making harmless snakes appear menacing using paper cutouts. Her intellect shines through her ability to curse in French and speak fluent Mandarin. On a trip to Okinawa, Toshito Kikuchi mentioned that she speaks five languages, yet ironically, she cannot understand her Gundam-obsessed roommates.
Her animosity towards teachers originates from elementary school experiences. Urumi's teacher, Ms. Fujimori, initially supportive, struggled to manage Urumi’s advanced intellect since she attended a second-rate college and it was her first year teaching. Urumi’s constant demands for attention, both in and out of school, and her interest in highly advanced subjects like differential calculus eventually overwhelmed the teacher. When Urumi publicly corrected Ms. Fujimori during a lecture, the teacher retaliated by revealing Urumi’s secret to the class. It can be inferred that her intelligence comes from her biological father, whom her mother selected solely based on his intellect, possibly an American scientific genius. This revelation caused significant psychological trauma to Urumi, leading to her understandable hatred of teachers. Ms. Fujimori’s last appearance in the story involves her pleading with Onizuka to help Urumi before something dire happens.
Urumi is later discovered by Miyabi in a small apartment and hired to torment Onizuka. Initially a student at Holy Forest, she stops attending regularly after some time. She frames Onizuka for lechery, landing him in jail overnight, only to show up in his class the next morning. Onizuka’s frustration escalates when Vice-Principal Uchiyamada warns him against physically harming Urumi due to her educational potential. Urumi manipulates Onizuka into becoming her "genie" by threatening to have him arrested after faking her death when he accidentally pushes her off a building.
However, everything changes when she encounters Ms. Fujimori again, reigniting her deepest hatred and directing her wrath at the student body. Onizuka responds by bringing his biker gang to school and “kidnapping” her from class. He finally reaches her by almost killing them both while jumping over a gap at a suspension bridge, despite her claims of fearlessness. Onizuka helps her move past her trauma, convincing her that her past isn’t worth ruining her present over. Inspired, she allies with Onizuka and assists him with his troubles.
Despite switching allegiance, Urumi continues her feud with Miyabi until Miyabi reveals Urumi’s origins to the student body. Urumi retaliates by creating a website promising to post pictures of Miyabi in her bathroom after a countdown timer reaches zero. However, the site reveals only a single photograph of Urumi, Miyabi, and Tomoko Nomura during their younger years. Urumi never intended to harm Miyabi; she just wanted to scare her. After attempting suicide at an indoor skiing arena, Urumi is rescued by Onizuka. This incident leads her to consider Onizuka her "favorite."
Urumi becomes deeply infatuated with Onizuka, even considering eloping with him. She often resorts to violence out of jealousy, beating Onizuka mercilessly whenever he tries to fulfill his perverted desires. Urumi tells Onizuka to wait for her hormones to kick in, confident she will have a desirable figure by then. Like Noboru Yoshikawa, her loyalty to Onizuka is so strong that she contemplates suicide if he were to leave, believing her life would be worthless without him.
