Hosuke begins as a talking owl suffering from amnesia, accompanying Sho Yamato and friends through the X-Zone. He displays a comical and sometimes perverse nature, often showing affection for Makoto, while offering the group occasional guidance. His owl form features distinctive light teal coloration and an unusually long tail.

His true identity is later uncovered as the former king of the X-Zone and grandfather to Yuki. Hosuke assumed the throne after his friend, Sho's father Takeshi Yamato, was accidentally transported to Earth through an interdimensional tunnel. Due to vastly accelerated time in the X-Zone compared to Earth, Hosuke aged into an elderly man during Takeshi's absence. To combat an ancient evil threatening his realm, Hosuke deliberately cursed himself into owl form, sacrificing his human body and memories of his past. This self-inflicted transformation explains his initial amnesia and fragmented recall of X-Zone lore and ancient language.

After Sho defeats the ancient evil possessing Takeshi, Hosuke regains his human form and memories. As the restored king, he oversees the stabilization of the X-Zone's energy and facilitates the return of Sho's friends to Earth. He later enables Sho to travel between Earth and the X-Zone, ultimately choosing to accompany Sho back to Earth and rejoin their human companions rather than remain alone in the X-Zone. In the aftermath, he witnesses reconciliation between former rivals, including Gabu and Taiga Samejima offering apologies for their past actions.