Gimmy Adai and his twin sister Darry were orphaned children raised by Rossiu Adai in the underground Adai Village. When new births breached the village's strict 50-person limit, the elder chose the twins for exile. Rossiu accompanied them to the surface, integrating them into Team Dai-Gurren.

Initially impulsive, cheerful, and reckless, Gimmy often contrasted with Darry's caution, sometimes leading the pair into trouble. During the Beastmen War, they served primarily in supportive, observational roles, witnessing major events like the capture of Dai-Gunzan and the battle of Teppelin.

Seven years later, during the Anti-Spiral War, Gimmy matured into a dedicated Grapearl Squadron pilot, routinely wearing the standard uniform and taking on increased combat responsibility. His emotional depth grew, revealing visceral fear during intense battles like the Super Galaxy Dai-Gurren's entrapment in ultra-dense space. He experienced profound distress over the deaths of comrades like Jorgun and Balinbow.

A pivotal moment came when Gimmy naively questioned why Simon's immense Spiral Power couldn't resurrect fallen allies. After receiving explanations from Yoko and Simon about accepting mortality and the importance of passing the torch to new generations, Gimmy achieved a mature understanding of sacrifice and legacy. This realization led Simon to deem him worthy of inheriting Lagann's Core Drill.

In the final battles, including the conflict depicted in *The Lights in the Sky Are Stars*, Gimmy actively participated in the space war. He rescued Darry after her mecha was damaged and witnessed further sacrifices that hardened his resolve. By the epilogue, twenty years post-war, he and Darry commanded the Grapearl Squadron and piloted the iconic Gurren Lagann, embodying Simon's legacy.