Jane The Killer, while superficially resembling Jeff The Killer in appearance, is in fact one of his former victims, resurrected and given supernatural abilities by means unknown. She is utterly obsessed with destroying Jeff, and her loyalties lie in the whatever side hates him more at the moment. At one point she was hired by Calypso to track down Jeff, but she quit when she discovered his true intentions.
"DON'T GO TO SLEEP!"
"You...want to turn all men, women...CHILDREN into machines?! You...you monster!"