Roll is a kind-hearted humanoid robot created by Dr. Light to be a house keeper, helping around Dr. Light's Laboratory by cleaning and cooking. She is the "little sister" of Mega Man and Proto Man. Roll is one of the few female characters in the original Mega Man series, and the only female humanoid robot until Plum and Splash Woman were introduced into the series. She was named to match her counterpart's name ("Rock" 'n' "Roll"), with Rockman being Mega Man's Japanese name.
Originally starting out as a minor character, she gradually became more prominent over the years (Starting in Mega Man 8, where she is able to help out with creating items from bolts (She would do this again in Mega Man 9)).
She appeared as a playable character in Mega Man: Battle & Chase, Mega Man Powered Up, Marvel vs. Capcom, Tatsunoko vs. Capcom, and a few others. In some games she uses a broom as a weapon, while in others she has a buster and can transform into a large combat robot.
She also plays a significant role in Ruby-Spears Mega Man, Mega Man: Upon A Star, Mega Man Megamix, and Archie Comics' Mega Man.