Eternal Soul

Trap Card {u}{b}(During your turn, you must first place
this card face down as an enchantment for {1}.
Cast it on a later turn for its Trap Card cost.)
When cast: Add 1 "Dark Magic Attack" or
"Thousand Knives" from your library to your hand.
All "Dark Magician" you control get hexproof.
When this (Face up) card leaves the battlefield, destroy
all your creatures.