Advance on the Populace

Invade 7 (Put seven +1/+1 counters on target
Demon you control, or create a 7/7 black Demon
creature token with flying.)
Creatures your opponents control get -1/-1 until
end of turn for each Demon on the battlefield.
Whenever one of those creatures dies this turn,
Invade 1. (Put a +1/+1 counter on target Demon
you control, or create a 1/1 black demon creature
token with flying.)