Gilded Cage~ Shapeshifter Rebirth

"You're just my tool. Know your place."
It's her duty to follow her master's command. Even at the risk of injuring herself or losing her mind.
It's his right to make use of her cold-heartedly. Even discarding her when she had become useless.
She was a bird trapped inside a gilded cage, slowly losing her mind in the process.
He was the heir of the country, regretting things he had lost in the process of power chasing.
Could she ever be saved? Could he get back what he had lost?
A love story between an antagonist and a side character.
Melancholic Sword Apprentice (hidden shape-shifter) × Cunning Cold-hearted Master of Ivory Manor