Master of Dark Rites is a rare Creature — Vampire Cleric card from The Lost Caverns of Ixalan Commander (LCC), collector number 83. Current market price: $4.63, TCGplayer market prices via Scryfall.
{T}, Sacrifice another creature: Add {B}{B}{B}. Spend this mana only to cast Vampire, Cleric, and/or Demon spells.