Horde Prime is all colors.

Hore Prime enters the battlefield with a Prime counter.

Whenever Horde Prime leaves the battlefield, exile him with a Prime counter on him. He cannot be returned to the command zone.

At the beginning of your upkeep and your end step, if you don't control a creature with a Prime counter, you may pay {2}, if you do put a prime counter on up to one creature you control, this ability only triggers from exile. If Horde Prime was your commander, that creature becomes your commander.

Creatures you control with Prime counters have all abilities of creatures you own in exile with Prime counters.