Ultraman

Utraman is a fan character of the Megaman universe.

Classic
Created sometime after the creation of the robot masters, Ultraman was comissioned to help the Anti-maverick forces. At once, he was teamed up with a robot named Abyssman. Going into combat, they both worked together to finish missions and destroy countless forces of mavericks. Just months before the end of the maverick wars, however, in an abandoned mine shaft underground, Abyssman betrayed Ultraman while on a mission to quell maverick activity in that area. Abyssman almost completely detroyed Ultraman, and left him underground, destroying the mine and causing it to cave in after the maverick forces had left the cave.

Zero
About a month after Zero was found, What remained of Ultraman was found deep beneath the earth by scientists. barely alive, the only thing left was his power source, which was keeping him barely alive all of this time.