Clavileño, First of the Blessed is a mythic Legendary Creature — Vampire Cleric card from The Lost Caverns of Ixalan Commander (LCC), collector number 2. Current market price: $0.72 (foil $0.42), TCGplayer market prices via Scryfall.
Whenever you attack, target attacking Vampire that isn't a Demon becomes a Demon in addition to its other types. It gains "When this creature dies, draw a card and create a tapped 4/3 white and black Vampire Demon creature token with flying."