Gamma is one of the many robots(or bandiks) created from the E-100 series by Dr. Ivo "Eggman" Robotnik. Gamma was built sleek and versatile, able to overcome most terrain. He was oringinally meant to be a fighting machine with his targeted laser-sight and precision arm-cannon. Like many of Eggman's bandiks, Gamma was powered by a mobian Flicky. During one of Dr. Eggman's campaigns, Gamma was sent to retrieve a Flicky that held a Chaos Emrald. This Flicky was not only protected by Amy Rose but was also the child of the Flicky within Gamma. The Flicky inside Gamma mixed with the progmaming of the robot and a new consciousness was born. After that Gamma went rouge and freed Amy and the baby Flicky, then waged war on the Eggman Empire.
Gamma spents almost two years fighting Dr. Eggmans's forces and purposefully seeking out and destroying the rest of the E-Series robots. Finally, Dr. Eggman had enough and sent out the final model of the final model of the line: E-123. Codenamed "Omega," this robot was a walking arsenal. Programmed with an inflated ego, Omega wanted to destroy Gamma quicky so that he could move on the more "suitable" targets - nameley, Sonic the Hedgehog. His mission ran into snag when he crossed paths with Shadow the Hedgehog, who was trying to recruit Gamma to Team Dark.
In and ensuing battle with Omega, Gamma was forced a confrontation on it's terms. As Omega prepared to strike, Gmma uploaded all of it's free will algorithms into him. Gamma was destroyed and it Flicky was freed, but not before Omega received the "free will" code. Omega now saw the world through Gamma's eyes - not full of targets, but with living things whose existances had meaning. Unable and unwilling to follow Dr. Eggman, Omega opted to take Gamma's place and join Team Dark. Now he could fullfill both his duties: protect the world, and do it in the most violent, pyrotechnic way posible.