The mutant master of multiplication, Jamie Madrox. Born with the ability to generate duplicates of himself after any kinetic impact, he spent much of his early life in relative isolation. After the death of his parents, he ran the family farm alone for a time, before crossing paths with the Fantastic Four.
Reed Richards crafted a suit for Jamie that helped him control his multiplication powers, and since that time, his natural control of them has increased. He is a longtime affiliate of the X-Men, and a member of the second incarnation of X-Factor.
Currently, he is experiencing a new issue with his powers : if duplicates remain too far away from him for too long a time, they begin to develop truly independent personalities, based on fragments of his own.