Shadows of the Frost

I was born alongside my sister, and the Oracle declared twin princesses to be an ill omen.
So Isabella was sent to the Frost Plains to be raised by our uncle.
The Frost Plains were harsh, and she couldn't endure the endless days and nights of martial training. When she tried to escape, enemy forces captured her, and she became a lowly slave.
Meanwhile, I was pampered and deeply loved by King Robert, destined to marry into Riverton and become their esteemed queen.
Isabella, filled with resentment, hid among my wedding entourage and poisoned me.
But unexpectedly, we were reborn.
This time, she was quick to draw the long stick that meant staying.
'Now it's your turn to taste the bitterness of the Frost Plains!' she thought.
But she didn't know that The Gilded Cage, which seemed so bright and beautiful, was the true hell.