Szarekh, the Silent King

Szarekh, costs {1} less for each artifact in your graveyard.
Menace, Ward - discard a card.
If an artifact, you control would be exiled from
the battlefield, return that artifact to your hand
at the beginning of the next upkeep.
{t}: add {b}{b} spend this mana only to cast artifact spells in your graveyard.