Yūta Hibiki is a high school student living in Tsutsujidai. He awakens with amnesia, initially recalling nothing before Rikka Takarada found him. This memory loss results from an unknowing possession by a fragment of Hyper Agent Gridman's consciousness, occurring after Gridman's defeat by Alexis Kerib. Believing itself the real Yūta, this Gridman fragment took control while the true Yūta lay dormant within. Fundamentally kind-hearted, Yūta prioritizes protecting his friends and city. He harbors a longstanding crush on Rikka Takarada. Though lacking his possessed self's experiences, he understands and forgives Gridman for the unintended possession, recognizing the circumstances of Gridman's battle with Alexis Kerib. Compared to the Gridman-possessed persona, the real Yūta displays greater emotional vulnerability and insecurity. He worries excessively about potential rejection from Rikka and feels disheartened by his perceived shortcomings when first fighting alongside Gridman. He enjoys others' company but was less socially active than friends Sho Utsumi or Rikka before the possession. Biologically, Yūta is not human but a Repli-Compoid, a human-like being created by Akane Shinjo using her Venoras. This artificial origin freed him from Akane's programming, allowing Gridman to choose him as a host. His physiology grants unique abilities, including perceiving Akane's concealed Venoras and seeing Gridman within the Junk computer. After his first battle, this ability passively extends to Sho and Rikka. He possesses the Primal Acceptor, a device on his wrist enabling him to merge with Gridman via the "Access Flash" command. This merger allows Gridman to materialize and fight kaiju, typically with Yūta in control, though time-limited by the Junk computer's processing capacity. Core relationships define his journey. Rikka Takarada, who discovered him amnesiac, becomes his close friend, object of affection, and fellow Gridman Alliance member. Sho Utsumi, another classmate, is his best friend and co-founder of the Gridman Alliance. Akane Shinjo, his creator and classmate, evokes complex feelings; he wishes to save her from Alexis Kerib's influence despite her destructive actions. Anti, a sentient kaiju initially obsessed with killing Gridman, develops a contentious dynamic with Yūta, eventually finding common ground against Alexis Kerib. Throughout the series, while possessed by the Gridman fragment, Yūta fights kaiju alongside Sho and Rikka. A critical juncture occurs when Akane stabs him, triggering a coma. During this coma, he confronts the truth: his amnesiac self was the Gridman fragment, and his true self lay dormant. Repaired by the Neon Genesis Junior High Students, the Junk computer awakens him. Regaining control of his body, he willingly merges with Gridman again to combat Alexis Kerib and assist Gridknight. In the climax, he participates in Gridman's final transformation to defeat Alexis and heal Akane's heart. After Gridman departs, his parents return, and he resumes his life. In subsequent events depicted in *GRIDMAN UNIVERSE*, Yūta navigates life as a second-year high school student, now separated from Rikka and Sho's class. He struggles with the lost memories from the two-month possession, feeling a sense of absence but holding no resentment towards Gridman. His insecurities resurface regarding Rikka, amplified by misunderstandings about her personal life. He actively tries to confess his feelings to her, demonstrating persistent but hesitant affection. When kaiju threats reemerge, he voluntarily becomes Gridman's host once more, exhibiting strong heroic willpower, notably agreeing without hesitation to a potential heroic sacrifice to restore Gridman. This action deeply worries Rikka. His willpower, particularly his determination to confess to Rikka, inadvertently aids allies in crossing dimensional barriers. By the narrative's conclusion, he successfully confesses his feelings, entering a relationship with Rikka.