Roll

Roll is a humanoid robot developed by Dr. Light. She is Mega's sister, and was designed to do household tasks.

She is shown to be capable of fighting in Harry Pothead Chronicles S1E4. Her Ultimate Combo is Ultimate Roll Combo: Shoryuken Deluxe.

Trivia

 * Roll was originally named after Rock so they'd be called "Rock and Roll" in conjunction. However, this was retconned in favor of keeping the "Mega Man" brand intact in America.
 * To make matters worse, if Mega Man Universe weren't cancelled, the franchise would be renamed Mega Man in Japan, further destroying this charming piece of trivia.