Aatrox, the Darkin Blade

Aatrox, the Darkin Blade gets +1/+1 for each other demon you control.
Whenever Aatrox, the Darkin blade attacks it gains lifelink until end of turn.
Whenever a creature dealt damage by Aatrox the Darkin blade this turn dies, untap Aatrox.
{1}{p/b}{p/r}{t}: Aatrox, the Darkin Blade deals 3 damage to target creature.