Real Name: Regan Wyngarde
Relatives: Jason Wyngarde(father), Martinque Jason(Half-sister)
Team affiliations: Hellfire Club/Sebastian Shaw, X-men, Marauders, Sisterhood of Evil Mutants
Creators: Chris Claremont & Salvador Larocca
Powers: Lady Mastermind possesses the mutant power to project extremely convincing and realistic illusions into the minds of others, the same ability her father had.
Her illusions are hypnotic, and her victims tend to accept them as fact, even when the images and scenarios they are confronted with involve sudden changes to the world around them, or are inconsistent or improbable (for example, Rogue, when under Lady Mastermind's control, did not question the sudden existence of a multitude of Vargases, or the random jumps in location and time she was experiencing). As such, they can be used as a very effective brainwashing tool.
Regan's powers can also kill, as her victims' bodies respond as if her illusions are real. She confronted Viceroy with the illusion that he was drowning, and believing it to be real, he suffocated, despite having no physical injuries and being in a room with sufficient oxygen.
Also her illusions can put enemies in a coma like state, by telepathically putting her enemies mind in a maze in which theres no escape, or trapping her victims mind.
In addition, unlike her father, both Regan and her half-sister Martinique have limited telepathic abilities that enable them to read their foes minds and make their illusions all the more accurate for it.