Ebonblade Reaper is a rare Creature — Human Cleric card from Onslaught (ONS), collector number 141. Current market price: $6.03 (foil $16.07), TCGplayer market prices via Scryfall.
Whenever this creature attacks, you lose half your life, rounded up. Whenever this creature deals combat damage to a player, that player loses half their life, rounded up. Morph {3}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)