A strange, protector, and noble human? or is it Demon?

Sweet memories of a child were the one thing someone should cherish - in her own right this is what she thought too. Once, now? She lived with powers beyond her knowledge and did not know how long she could control them. When will she give in? Will someone finally find her hurting something or someone and end her? It was a hope, at one point she did want to die - Until she met him.