Tempus, God of War

When Tempus, God of War enters the battlefield
put X +1/+1 counters on Tempest, where X is
the number of creatures opponents control.
As long as your devotion to red, green, and white
is less than 10, Tempus isn't a creature.
Remove a counter from Tempus:Target creature
must block or attack this turn if able.
Exile 20 cards from top library:Put Tempus from graveyard to battlefield.