Herald of Anguish is a mythic Creature — Demon card from The Brothers' War Commander (BRC), collector number 108. Current market price: $0.38, TCGplayer market prices via Scryfall.
Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.) Flying At the beginning of your end step, each opponent discards a card. {1}{B}, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.