Maximillion is a security droid that works for Jonar Carter, Booster Gold's father. When Jonar was sent the a million years into the past so was Maximillion. MAximillion was there when the Black Beetle saved Jon and brought him to Vanishing point.
Maximillion and Skeets, Booster golds partner droid, have done battle many times and have been labeled "arch androids". It is Skeet who finally rusts Maximillion to death.