Court of Embereth is a rare Enchantment card from Wilds of Eldraine Commander (WOC), collector number 24. Current market price: $5.84 (foil $5.45), TCGplayer market prices via Scryfall.
When this enchantment enters, you become the monarch. At the beginning of your upkeep, create a 3/1 red Knight creature token. Then if you're the monarch, this enchantment deals X damage to each opponent, where X is the number of creatures you control.