Oketra the True
Amonkhet — mythic
Legendary Creature — God
Oketra the True rulings:
2017-04-18: Once Oketra has attacked or blocked, it will remain in combat even if the number of other creatures you control becomes two or fewer.
2017-04-18: You don’t have to attack with three other creatures for Oketra to be able to attack. The same is true of blocking.