Ko’ Vero, Eldritch Swindler

Ward - Pay 4 life.
Whenever you cast a spell you dont own, its
owner loses life equal to that spells mana value.
At the beginning of your end step, exile the top
card of target opponents library face-down. Until
the end of your next turn, you may look at and
play that card, and you may spend mana as
though it were mana of any type to cast it.