Kagemaro, First to Suffer is a rare Legendary Creature — Demon Spirit card from Saviors of Kamigawa (SOK), collector number 73. Current market price: $2.97 (foil $20.00), TCGplayer market prices via Scryfall.
Kagemaro's power and toughness are each equal to the number of cards in your hand. {B}, Sacrifice Kagemaro: All creatures get -X/-X until end of turn, where X is the number of cards in your hand.