Great Duchess Sarah

Great Duchess Sarah is unblockable.
Whenever a Vampire you control deals combat
damage to a player, look at the top card of target
player's library. You may put that card on
the top or bottom of his or her library, or you
may cast it as though as it had Flash.
Whenever this card is put into a graveyard from
anywhere, shuffle it into your library.
"Blood is my brother's favorite weapon.
I prefer secrets..."