Heshveta Gravekeeper

{t}: Discard your hand, then draw the same
number of cards from your library, minus 1.
As long as Heshveta Gravekeeper is on the battlefield, you may cast spells from your
graveyard for half of their mana cost. You may
only cast spells from your graveyard. If your
library is empty, you do not lose the game.
Instead, shuffle your graveyard into your library.
Exile all spells you cast from your graveyard.