Beyond the boundaries

No amount of guilt can change the past, and no amount of anxiety can solve the future.
Aris tried to deny her identity, her loses, her sufferings. But they always return to her like an endless chapter of nightmares.
"You know who you are and you can't escape from your fate. Why don't you just accept it?"
Fate. Destiny. She hated those words. They were meaningless, useless. She was tired of everything. But she doesn't belong here, she's the daughter of the most powerful duke of Zeria Empire, Aris Sapphirus. She was brought up as a boy even though she was a girl for political reasons. She lost her parents, her best friend and teammates. She's tired of losing people, tired of not being strong enough to protect them. She and her younger brother are both tied with twisted fates. Will she be able to overcome them?
"Your parents... they're alive."
That was it. She couldn't take jokes about these. Not until when her adopted guardian, dr. Elrod was attacked by demons. Demons from her world, from her dimension, from her empire. That was enough to make her snap and return to being who she was, the knight of despair, of the cursed element, black flame. Her best friend was the wielder of white flame. But in the cruel destiny, it was written that they would have to kill each other. None can survive while the other lives. But reality hit hard her hard, her one and only friend died, protecting her.
"I hope you win the war you tell no one about." he turned to leave and added, "Our destiny is not written for us, but by us after all."
His words made her hopeful like a kid again.
But what is with all the fame and name if she's so weak that she can't even protect the ones she loves? Will she... find happiness? Are her parents alive? Will she be able to protect her brother, her first and foremost, sole aim?