They were once one, Shade was cursed from birth with a Darkspirit, this Dark half grew stronger as he grew older and eventually Shade began to lose control and the demon that came to call itself Venom took over terrorising innocents but Shade did his best to hold him back but it became harder and harder until the shift to Venom became almost permanent. Wraith who was good friends with Shade had Masque (Wraiths Advisor and magical expert) perform a ritual to expell and destroy the Darkspirit, it work at first but Venom refused to perish and in stead escaped becoming more powerful without Shade's goodness to hold him back. Shade was left completely pure while Venom became a being of pure darkness and evil relishing in pain and suffering torturing for fun. He delights in capturing victims and exploiting their worst fears as a method to make them suffer until he's had enough before slowly killing them. There is no worse being in existence, even his physical form has decayed to the darkness making him almost impossible to harm. Fortunately Mystique created a Collar and managed to get it around Venoms neck, the collar dampens Venoms near limitless power and can only be removed with Mystiques Necklace, as such Venom has an enormous hatred for Mystique and wants her to suffer before he takes the necklace and unleashes his full power