Liliana is a human Planeswalker and master of necromancy, using it to reanimate the dead, corrupt the living, and unlock power from death. She's charismatic, witty, and attractive, but profoundly egocentric. Though she appears to be in her 20s, she is actually over a century old. At some point in the past, she made a deal with four demons to secure her youth and power in exchange for her soul. The demons have kept their side of the bargain, now it's her turn to obey, but she isn't going to play by their rules.
A replica of some sort of Liliana's was found in Ravnica battling outside a church of Orzhov against Garruk Wildspeaker. While it appears that Garruk was fighting for no reason other than Liliana is a challenging hunt, Liliana herself was after something else. What could the Piece of Stone she sought be?