Aatrox, the Darkin Blade

When this creature destroys another creature,
put a +1/+1 counter on it and you gain 2 life.
During your turn, when Aatrox, the Darkin
Blade deals damage to anything, you may pay
{w/b}: it fights target creature you don't control.
{2}, Discard a card: Discover a Darkin equipment.
Choose Background The World Ender.