The psionic entity Malice was recruited by Mister Sinister to join his Marauders. On assignment, Malice manipulated the desires of Dazzler to be loved, which led to her come out of hiding, in order to draw out the X-Men. This worked, and Malice then proceeded to possess Rogue, Wolverine and Storm. But Storm's will was too strong, and she forcibly ejected Malice from her body.
During the Marauders attack on Polaris, Malice possessed the powerful mutant. As their two energy matrices interwove, the two women became permanently bound together. Mr. Sinister had known this union would occur, but failed to warn Malice of it because he had specific plans for the now-blended entity: using the Malice-possessed Polaris to attack the X-Men, who counted among their team members Polaris' lover Havok.
Malice was later freed from Polaris' body when Zaladane temporarily stole Polaris' magnetic powers.
Eventually Malice found her way back to Polaris, but angered over being forced from Polaris' body, she instead possessed the body of Polaris' then-lover, Havok. On vacation from their job as government operatives in the X-Factor group in Honolulu, Hawaii, the Malice-possessed Havok attempted to kill Polaris, but was stopped by Mister Sinister, who wanted Polaris alive for his own unknown plans. After taking Polaris to safety, he ordered his Nasty Boys to do anything short of killing Havok in order to rid his body of Malice. With the rest of X-Factor arriving mid-battle, the Nasty Boys were forced to halt their assault when Strong Guy and Wolfsbane perceived Mister Sinister to be abducting an unconscious Polaris while the Nasty Boys held Havok at bay. After a quick battle Polaris regained consciousness and revealed Malice's possession of Havok, then attempted to force Malice from him. Mister Sinister instead instructed Malice to possess Polaris, which forced Havok and Polaris into a mental struggle over who would possess the non-corporeal mutant (both wanting to sacrifice themselves to spare the other). Eventually, forced from both bodies, Malice's corporeal essence floated free, where it was apparently destroyed by Mister Sinister.
Malice (or someone using the same name) returned as a digital entity instead of a psionic one, taking possession of Omega Sentinel via email virus.
Malice has recently been able to "gather" her corporeal essence and get back to life again, and started to posses people in New York. Cyclops was able to detect her (possible with the help of Cerebra). While tracking her on a subway train he ran into a fight with Spider-Man. Malice was able to posses Cyclops for a few seconds before she was knocked unconscious by Spider-man that took the possessed Cyclops to his lab and separated Malice from Cyclops and put her in a containment box that he gave to Cyclops.
Malice is a being of pure psionic energy that can merge with the mind of another sentient creature. While people are possessed by her, a black necklace/choker with a silver medallion appears on the victim.