15 Video Game Heroes Who Became Villains 

Sigma – Mega Man X Series

The sheer number of times that Capcom found a way to bring back Sigma to the Megaman X series might be somewhat mockable as they became more and more ridiculous, but he wasn’t always the rebellious, viral leader of the maverick rebellion. That happened differently depending on exactly what story you chose to tell, but whether through a Wily virus inherited through a confrontation with a feral Zero, or a nihilistic outlook that wanted to push X’s ‘Potential’ for Reploid evolution, the former maverick hunter would leave many bodies in his wake, both robotic and otherwise.