Indiana, Roguish Relic-Seeker

Whenever Durnan attacks, look at the top
four cards of your library. You may exile a
creature card from among them. Put the rest
on the bottom of your library in any order.
For as long as that card remains exiled, you
may cast it. That spell has undaunted. (It costs
{1} less to cast for each opponent.)
Choose a Background (You can have a
Background as a second commander.)