Yeah sometime in his life his brother, Tronallus, and him get into a real big scuffle. His brother took him by surprise and so he had the upper hand of the aerial battle. Scratched out his eye and ripped his arm off and left him to tumble to his death in the vast seas of Jal. Thinking that he was dead the dark brother left him to drown.
Wounded and broken Oryonallus was carried to shore by sea creatures then left to be tended by friends who eventually found him. Now with a mechanical arm and optic the dragon doesn't let this slow him down nor beat at his confidence as he will repay his brother for the scars he had given him and hope that one day he could settle their conflicts to a close.