Seiya Uzaki, a fourth-grade student at White Dove Academy, is Ririka Moriya’s childhood friend and next-door neighbor. The son of a doctor with average academic standing, he aspires to emulate his father’s medical career while maintaining a mischievous, playful persona as the class clown. His humor often manifests in lighthearted teasing of Ririka, masking his unspoken romantic feelings for her, which she remains oblivious to. A video game enthusiast and sports fan, Seiya initially observes the interdimensional conflict against Dark Joker from the sidelines until discovering Ririka and Kanon’s secret mission. After Kanon’s incapacitation by the Black Vaccine, Seiya inherits her psionic powers, thrusting him into the conflict’s core. The anime accelerates this transformation, granting him immediate psychic abilities like energy projection and shields, whereas the manga depicts a slower evolution—first wielding a tactical boomerang before embracing combat roles.

Initially defined by comedic antics, Seiya matures into a resolute protector, confronting his blood aversion—a hurdle for his medical ambitions—through battlefield trials. His loyalty to Ririka fuels daring, untrained interventions in fights, while his strategic ingenuity counters enemy plans. When Dark Joker resurrects Kanon temporarily, Seiya alone discerns her manipulation, challenging others’ denial. Beyond Ririka, his dynamics include a rivalry-turned-partnership with Dewey, a former Dark Joker operative, as they dismantle the organization’s remnants post-Kanon’s departure. Mimina, Queen Helena’s sister, complicates his life with unreciprocated romantic advances, adding interpersonal tension.

The manga emphasizes his gradual assimilation into the conflict, contrasting the anime’s swifter elevation to frontline psychic combatant. Both iterations, however, chart his growth from secondary jester to indispensable strategist and warrior, balancing levity with introspection. His legacy crystallizes in unwavering devotion to Ririka’s safety and his pivotal role in uniting Earth and Queen Earth against annihilation.