E-123 Omega

E-123 Omega is a robot from the same world as Sonic the Hedgehog. Created by Dr. Eggman, he rebelled against his creator and joined Team Dark alongside Shadow the Hedgehog and Rouge the Bat.

Worlds Collide
Omega joins forces with Sonic and Mega Man's team of heroes, namely: Espio the Chameleon, Vector the Crocodile, Charmy Bee, Proto Man, Amy Rose, Miles "Tails" Prower, Knuckles the Echidna, Rush, Shadow the Hedgehog, Silver the Hedgehog, and Blaze the Cat. Having located the Wily Egg, Dr. Eggman and Dr. Wily's base of operations, the group faced off with a massive army of Robot Masters who had been time-cloned by the doctors to defend the flying fortress. Omega quickly proved his superiority to Napalm Man, before setting out to rescue his teammate Rouge the Bat, who had been transformed into the Roboticized Master Rouge Woman. He then fought alongside the rest of Sonic and Mega Man's allies for the duration of the battle with the Robot Master army, until the Super Genesis Wave washed over them all. (Sonic the Hedgehog #250-251)

Worlds Unite
Omega has a brief appearance while the Unity Engines are combining the worlds of Sonic and Mega Man. Omega, Shadow, and Rouge, are inside a G.U.N. carrier that is merged with the Mayor's government building, causing it to explode and apparently killing all inside. However, these events were later reversed by the actions of Xander Payne.