Lovely, of the Silver Castle

Vigilance
At the beginning of each end step you may exile an instant card from your graveyard, you may cast the exiled card anytime as long as you control a Demon creature. Cards exiled this way cost {w}{b} less to cast.
Whenever a creature leaves the battlefield due to an Instant card effect, destroy target nonland permanent an opponent controlls. This ability triggers only once each turn.