{1}, Reveal X black cards from your hand, Sacrifice Martyr of Bones: Exile up to X target cards from a single graveyard.
A card that’s already revealed for another cost or because of an effect can be revealed to pay this cost.
Each card that’s revealed to pay the cost remains revealed until the ability leaves the stack.
If one of the cards that’s revealed to pay the cost leaves its owner’s hand before the ability resolves, it stops being revealed, but the value of X is not affected.