On my Suggestions post someone asked me to do High Destructive Dragon however as I said I might take an idea and change it which is what I did. And everyone knows about the dinosaurs being killed by a meteor. They are also related to dragons, besides Extinction is like Destruction which I have always thought should definitely be in the game but there is already legendaries about this. And I do not think that there is some sort of Extinction Dragon in Dragon City yet so, here is my version or idea.
Possible Elements: Chaos, Primal, Nature and Fire.
Trained Moves: (Chaos) The End, (Primal) Archaic Roar, (Nature) Rotting Spell+
Beginning Moves: If you want please suggest, (Chaos) Destiny Chains, (Primal) Slash of Ages, (Nature) Leaf Blast, (Fire) Lava Balls
Source: Limited Time
Description: Famously known to have wiped out the dinosaurs, no one dare messes with him. He destroys opponents in the blink of an eye in the Arena. If you are lucky enough to be-friend the High Extinction Dragon he will ferociously fight for you and usually he does not lose.
Special Move: Yes
Skill: (The End) Deals extra damage while hitting all remaining opponents
To get this special skill you must collect the Creation Stone and the Destruction Stone in some events.