Rough story idea: Was considered an extraordinary fighter/royalty/army general(?), a major attack trapped and killed most of her clan, the survivors could not find her. Was cooled/stuck for centuries without a way to relight and covered in snow and ice over time (assumed dead). A traveler/excavator/hiker/archaelogist (can't decide, depends on my other dragon story plans who finds her!) found her, was able to relight her. Has incredible strength and power, but never fully recovered which is why she is obsidian/charred/sooty/idk the right word right now. Is now a pacifist.