Also called Mega, Omega-Xis is an AMian who went to planet FM, and stole the Andromeda Key in Star Force 1. He went to Earth and met Geo, a fifth grader in Echo Ridge. Omega had talked to Kelvin Stelar, Geo's father, at the space station that wanted to achieve communication with the FMians, who brutally attacked the space station called 'Peace'. Kelvin got stuck on the space station, wanting to get home. Omega turned him and his team on board the station into EM waves so they could drift through space to get to Earth. Omega and Geo were always being chased and targeted by enemies, forced to fight back in a form called "Megaman", which is a EM wave change between Geo and Omega. Omega had learned many things with Geo, while he always likes to fight. Later on, after Geo cut his brother-bands, Omega left Geo but not without defending the key. By the time Geo finds Omega, he was being attacked by every FMian that attacked them wanting to steal the Andromeda Key, except Lyra (Harp), and finally stole the key and gave the key to the FMian King, Cepheus. Omega was sorry but he tried to hide most of those feelings. Omega then ended up telling Geo some of the secrets, some of which was told by the satallite Admins; Leo, Pegasus and Dragon.
In the most recent Star Force game, Star Force 3, Geo's Star Carrier get's an upgrade which registers Omega-Xis as a Wizard. In the game, he is more freely shown in public, due to Wizards becoming very popular among most people. Also, in Star Force 3, Megaman's image is slightly changed. Omega-Xis' head is no longer the Megabuster. Instead, a more gun-like weapon replaces it.