Gregore Garosh was a soldier in the elite Red Shoulder Battalion of the Gilgamesh Confederation during the Hundred Years War. He served under Commander Yoran Pailsen alongside Chirico Cuvie, Byman Hagard, and Murza Melym. During the war's final stages, Garosh took part in a secret mission that ended with him sustaining multiple gunshot wounds. This mission fostered a vendetta against Pailsen within Garosh and his comrades.

After the war ended and the Red Shoulder Battalion disbanded, Garosh actively sought out his former teammates. He organized their reunion in Bakara City, where they salvaged and repaired damaged Scopedog Turbo Custom units from scrap. Garosh provided leadership during this preparation, mediating conflicts between Hagard and Melym while keeping them focused on their goal. He piloted one of the rebuilt Scopedogs, transporting the group towards Pailsen's suspected stronghold in the Belaida Plains.

During the assault on Pailsen's compound, Garosh engaged in combat against Blood Sucker armored troopers and the Perfect Soldier Ypsilon. When Ypsilon attacked Chirico, Garosh intervened, grappling with Ypsilon's Blood Sucker unit to allow Chirico's escape. This act led to Garosh being overpowered and killed when Ypsilon repeatedly punched the cockpit of his Scopedog.