The Royal Guard had existed for some time as the protectors of the House of Acorn and the kingdom, with its membership including the young Antoine D'Coolette. The guard came to Princess Sally's aid when Metal Sonic attacked her in Mobotropolis Shortly before the Shattered World Crisis began, but were woefully outmatched by the robotic Hedgehog. Fortunately, Sonic the Hedgehog arrived just in time to save the Guard from worse injuries, and several guardsmen were present upon Sally's reunion with her father King Acorn. Sadly, the next attack on Mobotropolis came from M'egga Man of the Roboticized Masters, who decimated the guard easily on his way to Castle Acorn. They were later amongst the residents of Mobotropolis and Mega City aided by the Knothole Freedom Fighters and Wily's Robot Masters as Mobius and Earth 20XX were fused together into a Unified World. (StH: #256; SB: #8; SSD: #8; MM: #50)
Following Worlds Collide, their outfits include white berets and belts, with some members wearing additional clothing.