Emma Frost

Emma Frost is a character from the X-Men franchise. At first she is a villainess, but later she becomes a heroine.

As a member of X-Men, Emma deals with her emotions from murdering her sister and travels to the mutant haven island of Genosha where she teaches at a mutant school until a genocidal Sentinel attack kills most of the island's population including all of her students; Emma survives due to the sudden manifestation of her secondary mutation: the power to transform herself into a flexible, near-invulnerable, diamond-like substance. Emma then joins the X-Men after they rescue her from Genosha, and takes on a teaching position after the Xavier Institute reforms into a regular school. She starts to look after and train a group of telepathic quintuplets, the Stepford Cuckoos, who quickly become her prized pupils. Frost and the Cuckoos prove themselves when they help fight and defeat Charles Xavier's evil twin sister Cassandra Nova. As a member of the X-Men, Frost begins a psychic, non-physical, sexual relationship with Cyclops, who had become distant from his wife Jean as a result of his temporary physical and mental merger with the ancient mutant Apocalypse and added disconnection from Jean "remanifesting" the Phoenix Force. Emma and Cyclops' psychic meetings begin in the form of therapy, but soon turn into a telepathic romantic affair.
 * For Emma Frost's incarnation in the animated series Wolverine and the X-men, check here.