Akatosh, Dragon God of Time

Flying, Indestructible, Shroud
•Akatosh costs {1} less to cast for each Dragon
creature that has been exiled this game.
•Akatosh cannot attack or defend unless a Dragon creature has been exiled this turn.
•Akatosh's power and toughness are equal to the
number of Dragon creatures in your exile.
{bull}Creation — If Akatosh deals damage to an
opponent, you may put one exiled Dragon creature
onto the battlefield under your control.