Beyond the extremities

Aris, having the habit of walking alone at night on the streets near her house encounters a strange boy, her age, who came with the request Aris was certain she would be asked sooner or later, asking her to return.
"You know who you are and you can't escape from your fate. Why don't you just accept it?"
Aris knew exactly what he was talking about, but does she even have a reason to return?
"Your parents... they're alive."

Aris is a thirteen-year-old girl, living a normal life with her younger brother, Axel and an adoptive grandfather, Dr. Claude Elrod; a scientist. However, her problems aren't as normal. She is from a different world, a different kingdom, a kingdom full of magical beasts and demons, a place beyond the boundaries and she knows it, yet hides it. She has no aspiration of returning to the place she came from.

Aris' parents were the grand duke and duchess of the Zeria Empire. Three years from now, Aris' parents were killed in front of her eyes. It was planned, someone close to them must have treacherously betrayed them. Assuming the right time, Aris picked her brother up, who was a baby back then, and made a break for it.
For all these years, Aris' sole aim was to protect her brother from the demons at all costs.
Who was the boy? Will she be able to protect Axel? Why are the demons targeting Axel? And at last, does she truly have to return to the place where she belongs and continue to live the life she was meant to live? Did Aris' parents actually die?
Though Aris is young, her aims, deeds and powers exceeds many other mages and knights of her kingdom. The hardships and challenges she's going to face until the demon king is defeated... will there be any end to that then?
As the challenging story goes on, Aris will meet many more interesting, unique and supportive people around her who will help her in her mission.