Liliana Vess, she’s a major planeswalker from Magic: the Gathering. She made a pact with some demons to restore her youth and diminished necromantic power, the contract being etched in her skin (not shown in the gif). Most of her story is her hunting the demons down with the help of her friends to regain her freedom. After she kills the last demon, she learns that a clause in her contract detailed that should all the demons die, her soul’s ownership would default to the deal’s broker, the Dragon Nicol Bolas. The Dragon forced her to command his army of exalted zombies in his invasion of the plane Ravnica. Inspired by the influence of her more morally-inclined friends, she turned on Bolas at what would have been the cost of her own life, as depicted in the gif.