Yuuzuru Oozora, recognized as Zuru Zora in English adaptations, appears as a timid, socially awkward classmate of Ikki and Arika, masking his secret role as the vengeful vigilante "Mystery Medarotter." Driven by resentment toward Death Medarots—technology created by his father, Maizuru Oozora—he blames these machines for corrupting their familial bond. To dismantle them, he adopts ruthless methods under his alter ego, targeting Death Medarot users unprovoked and treating his combat-focused Medarot, Dorcus, as expendable, casting ambiguity on his moral stance despite his protective intentions.

To preserve his unassuming image, he employs DonDoguu for everyday interactions. His tactics grow more complex when he temporarily integrates DonDoguu’s Medal into a Tyrrellbeetle and pilots the Death Medarot Excise, conflicting with his opposition to the technology. His journey forces him to confront the hypocrisy of his extremism while engaging in pivotal battles, such as opposing Kokuryuu Kamizake’s scheme to supplant traditional Medarots with emotionless Death Medarots. This culminates in a coalition assault on the Death Medarot Company headquarters to halt Kokuryuu’s plans.

Functionally, Yuuzuru’s narrative compensates for absent characters like Kouji Karakuchi, Phantom Retort, and Rokusho, positioning him as a dual antagonist-protagonist whose struggles reflect familial estrangement and the dangers of ideological absolutism. His story remains confined to the primary anime series, with no expanded portrayals in supplementary media.