Ga-Keen, also known as Gacky, originates from the robot featured in Magnerobo Ga-Keen. She fights alongside the Toei Robot Girls Team T, protecting Earth from alien threats by channeling the data of historical giant robots into human forms. Gacky shares a close bond with Gai-chan, the Gaiking-based team member, and actively aids her, notably during a sports festival race where both Teams T and Z faced disqualification due to excessive track destruction and rule violations.

She pilots the Delivery multipurpose vehicle, which shifts between motorcycle and aircraft configurations for transport and combat missions. Gacky is a dedicated martial artist, drawing inspiration from fighter Andy Hug, highlighting her commitment to physical training and combat skill.

Later, within the Robot Girls Z ONLINE storyline, Gacky undergoes a radical transformation via the "Team T Legend Plan," evolving into Earth Gacky. This powerful upgrade grants her a new form complete with a pickaxe weapon and distinct knickerbocker-style attire, significantly enhancing her abilities.