A boy from Adai village, an underground village where the people worship Gunmen as Gods. When Gimmy and Darry are chosen to leave the village, Rossiu decides to go with them and they join the Gurren-dan.

Spoiler

In Part 2, Rossiu is second in command to Simon over New Kamina City. With this newfound responsibility, Rossiu leads an investigation on Lordgenome's memories to learn more about the Anti-Spirals. The results he finds cause him to lose faith in Simon's leadership and imprison him in a desperate attempt to save humanity from the Anti-Spirals