Gospel of Geth

When Gospel of Geth enters the battlefield, put
the top half of your library, rounded down, into
your graveyard. Until end of turn, you may play
cards from your graveyard. At the beginning of
your end step, sacrifice Gospel of Geth. When
Gospel of Geth leaves the battlefield, shuffle
your graveyard into your library.
Gospel of Geth can be your Commander.
"The world is a book that can be opened and closed."