Guts, The Black Swordsman

Firststrike
When Guts, The Black Swordsman enters the battlefield you may have it fight target demon or god creature with converted mana cost x if creature dies exile it instead.
Guts, The Black Swordsman toughness is equal 1+ all demon/Gods on battlefield.
{x}{t}: Guts, The Black Swordsman fights target creature this turn if creature dies exile instead. Then shuffle Guts,The Black Swordsman into owners library