Bond of Doom and Deceit

When Bond of Doom and Deceit enters the battlefield, create a 2/3 blue and black Bird creature token with flying and a 1/2 blue and
black Human Knight creature token.
Creatures you control that are both blue and black have "Whenever this creature deals combat damage to a player, that player puts the top X cards of their library into their graveyard, where X is this creature's toughness."