Warleader's Call is a rare Enchantment card from Murders at Karlov Manor Promos (PMKM), collector number 242p. Current market price: $7.68 (foil $6.69), TCGplayer market prices via Scryfall.
Creatures you control get +1/+1. Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.