Winter, Tormented Loner is a uncommon Legendary Creature — Human Warlock card from Reality Fracture (FRA), collector number 307. Current market price: $0.36 (foil $0.41), TCGplayer market prices via Scryfall.
When Winter enters, you may sacrifice a creature or planeswalker. When you do, each opponent sacrifices a creature of their choice. Winter gets +1/+0 for each creature and planeswalker card in your graveyard.