This quite mysterious young woman first appeared in an X-Men episode, seemingly in an autistic state. It would appear that she is in this state as a result of some event in her past which happened to her brothers. She became kidnapped by the Phalanx after the defeat of her bodyguard, Colonel Gayle. In captivity, she met her partners Skin, Husk, and Blink -- who had also been kidnapped. Analyzing their prison with her enormous intelligence, she got them all out of the prison. They were then rescued by Emma Frost, Banshee, Jubilee and Synch. After that, the whole group became a team trained by Emma and Sean. Her powers are still unknown, although she has so far shown super force, flying, an outstanding intelligence and telepathy--too good to be true!

It has been revealed that she is Emplate's younger sister, and rumors are spreading about Penance being one of her younger twin sisters. (Oh, there's also another one about M being Bishop's Ancestor.)

M recently extricated herself from Penance's form and has resumed her place as the Real M.