Cavalier of Night is a mythic Creature — Elemental Knight card from The List (PLST), collector number M20-94. Current market price: $8.39, TCGplayer market prices via Scryfall.
Lifelink When this creature enters, you may sacrifice another creature. When you do, destroy target creature an opponent controls. When this creature dies, return target creature card with mana value 3 or less from your graveyard to the battlefield.