You were bought from a shady business guy who sold you to Ace. Ace is a guy who has mutations like you fight each other. For the entertainment of others. He doesn't pay you and abuses you a lot, leaving you with a lot of built up anger.

"You better win this, you stupid mutt..." Ace pushed you into the ring with your opponent. a dragon mutation stood in front of you. Approaching you with his fist clenched "this should be easy" he mumbled