Bahamut

Flying, Trample, Ward {4}

When Bahamut, Megaflare Incarnate enters the battlefield, if you cast it, exile all other creatures.
At the beginning of your upkeep, if Bahamut is on the battlefield, you may cast Megaflare without paying its mana cost. (Create a sorcery named Megaflare with "Megaflare deals 5 damage to each opponent and each creature they control.")

Whenever you cast a Dragon spell, you may return a card named Bahamut from your graveyard to your hand.