White Pawn

Haste. Whenever Black Pawn deals combat damage to
an opponent, put a rank counter on it.
Whenever a pawn creature deals combat damage
to you the turn it enters the battlefield, you may
tap Black Pawn. If you do, destroy that creature.
Activate this ability only if Black Pawn has four
or more rank counters on it.
Sacrifice Black Pawn: Search your library for a
creature card and put it onto the battlefield tapped.
Activate this ability only if Black Pawn has six or
more rank counters on it.