Avaria Kos, the Windstorm

Flying, vigilance
Avaria Kos, the Windstorm cost {x} less to cast,
where X is the amount of each creature with
flying in your graveyard.
Whenever you gain life, put a +1/+1 counter on
each other creature you control.
When Avaria Kos, the Windstorm enters the battlefield, gust 5.