[@Prince of Seraphs] I'm sorry I meant to put that in her CS. I'll edit it.

Anyway, her mother was the former Winter Queen. When she passed on Arys fought for and took the throne from her murderous cousins, who she then froze solid. They are several of the frozen corpses that decorate her hall.
She is young for a fae, not having been ruling that long. About 500 years or so, give or take a century. But she herself is around 1200 years old, again give or take a few years.