Sven, Burning Blade

Whenever Sven attacks, its power becomes equal
to the highest power among creatures defending
player controls.
Raid —At the beginning of your post-combat
main phase, if you attacked with a creature this
turn, look at the top card of each opponent's
library. You may cast each nonland card from
among them with converted mana cost less than
Sven's power without paying its mana cost before
the end of turn.