Aeos, Aether King

Aeos, the Aether King enters the battlefield with X +1/+1 counters, where X is 1/5 of the amount of energy you have Rounded down.
1WUBRG: You gain X energy, where X is equal to the number of +1/+1 counters on Aeos.
When Aeos, the Aether King deals combat damage to a player, put a +1/+1 counter on it.