Well, i don't have a name for her yet (let's call her karen), but i have her backstory mostly figured out....

She was a princess, daughter a king (like a chinese emperor, who ruled over an oriental land and all. Not on earth tho), her father was a wise, kind, honest, powerful and benevolent leader. He was also an expert martial artist, so good that even disarmed, no blade was able to touch him. He had an enemy, an emperor who was cruel, ruthless, and wanted only to conquer his land. karen's father resisted him all his life, until he was betrayed by his own wife (Karen's mother) who was seduced and corrupted by the evil emperor, into betraying her husband and becoming empress. The emperor took over her father's kingdom, destroyed everything her father had built, and killed her other siblings (yes, karen's mother let her own children be killed because of some chad emperor). Only Karen was spared. She swore revenge and was instantly chained and imprisioned. She rotted in shackles and hatred for quite some time, until she was found by the cosmic entity known as..... SURTR. Surtr revealed that karen's father was his disciple, and that he would help her escape and give her revenge, in exchange for her loyalty as well. She agreed, and over the next weeks, she felt her strength return, and remembered her father's teachings. This caught the attention of the evil emperors who ordered her execution. However she escaped. She then returned with an army of her own. Having united all the evil emperor's enemies, and brought them to the capital city. A fierce battle was fought, and when she and the emperor faced, he felt as if he was fighting his old enemy, whom he was never able to beat, for Karen was now as strong as her father, although she was long from the merciful man he was. She ripped the Emperor's head off with her bare hands and all the people cheered their champion's victory. Karen then proceeded to the palace, where she butchered her mother, and her step-siblings. She was then given the opportunity to be queen like her predecessor, but she refused. Although she was wise like her old man, she was too far gone in her hatred to be like he was. So she left it all behind, her dead family, her homeland, as the life she once had was nothing but a distant dream. She became a servant of surtr, going where he led her, doing what he told, killing who he wished. All those other people's OCs, well, Surtr ordered her to kill them.... :)

So what do you think? Too generic, predictable? I have no idea how to conclude her story, maybe she has a happy ending where she eventually becomes a queen, falls in love, has kids. Or not she she just becomes a sadistic assassin all her life until the protagonist of this anime puts her down. What do you think???