Gimmy, also known as Gimmy Adai, is a boy from Adai Village who was originally cared for by Rossiu Adai. He is introduced as a secondary character, but his presence and importance grow as the story of the movie progresses. Gimmy is the older twin brother of Darry, and the two are almost always seen together. Their early life in the underground village was marked by hardship. When the village population exceeded its strict limit of fifty people, two individuals were chosen to be sent to the dangerous surface world. Because Gimmy and Darry were orphans with no parents to advocate for them, the village elder selected them. However, Rossiu chose to accompany the twins rather than let them face the surface alone. The trio is found by Team Gurren, who allow them to join their group, setting Gimmy on a new path.

In terms of personality, Gimmy is defined by his impulsive and outgoing nature, especially when compared to his twin sister. He is the more reckless of the two, which often leads the duo into trouble. During the first part of the story, he almost always maintains a joyous and energetic demeanor, bringing a sense of youthful innocence to the team. He and Darry are often left to their own devices around the Dai-Gurren, but they are also frequently seen wanting to be around older female figures like Yoko or Nia. Despite his youth, he is not naïve to the horrors of battle. As the fight against the Anti-Spirals intensifies and he witnesses the deaths of comrades like Jorgun and Balinbow, he shows profound distress and is gripped by fear. In one instance, he is struck with terror when the Super Galaxy Dai-Gurren becomes trapped, momentarily wanting to join the fight but finding himself unable to move because of his fear.

Gimmy’s primary motivation initially is simply to survive and be part of the team, looking up to the older members as heroes. As the story progresses, his motivation shifts toward a desire to understand the world he is fighting for and to become strong enough to protect it. A pivotal moment in his development comes when he naively asks Simon why he does not use his colossal Spiral Power to bring fallen friends back from the dead. This question stems from a child’s simple belief that an all-powerful hero should be able to undo any tragedy. After a brief explanation from Yoko and further elaboration from Simon, Gimmy comes to understand the nature of loss, acceptance, and moving forward. It is this newfound understanding, this growth beyond childish naivety, that proves him worthy in Simon's eyes. As a result, Simon bestows upon Gimmy the Core Drill, the key to piloting Lagann, signifying that Gimmy has passed an important test of character and is ready to inherit the legacy of Team Dai-Gurren.

His role in the story evolves from being a passive observer and source of comic relief to an active participant and eventual successor. In the early battles, he and Darry primarily act as cheerleaders for the heroes. However, following the seven-year time skip, Gimmy has matured significantly. He is deemed responsible enough to pilot his own Grapearl, a mass-produced mecha developed from research on Gurren Lagann. He and Darry become commanders of the Grapearl squadron, piloting custom-colored models that symbolize their leadership status. He participates directly in the battles to defend Kamina City and in the first space battles against the Mugann. His key relationships are central to his character. His bond with his sister Darry is unbreakable, and he rushes to rescue her when she is shot down in an explosion, an act that costs their allies Jorgun and Balinbow their lives. He also shares a deep connection with Rossiu, who was his caretaker, and with Simon, whom he comes to understand as more than just a hero who can punch through reality. By the film's end, in the epilogue, he is seen alongside his sister as the new pilots of Gurren Lagann, having fully stepped into the role of protector.