Kept as a Prisoner by the Enemy Emperor After My Kingdom Fell

A heroine who grows over time. The leads are enemies at first, then he becomes fiercely doting later.

The male lead is a tyrannical emperor who takes what he wants, an obsessive, domineering madman. The female lead is innocent at first, then becomes a little scheming later.

The Western Chu Kingdom fell in a single night. On the night its city fell, flames soared into the sky. In the Golden Throne Hall, the empire's most beloved Ninth Princess nearly had her throat cut by an executioner. Just then, Shen Xiangsi saw the executioner who had destroyed her kingdom: the Northern Qi emperor, the most cruel tyrant in the land. The Northern Emperor wore black armor and held a seven-foot sword that gleamed with a cold light. He looked like a devil from hell. He walked up to Shen Xiangsi and looked down at her like an ant, the corner of his mouth curling in disdain. “So you're Princess Xiangsi of Western Chu... Those innocent eyes of yours are quite nice...”

The Northern Emperor discovered that the little thing from back then was becoming harder and harder to raise... and had even started biting him when she got angry...

And in the end...

He kept her caged by his side. After ten years together, she had become the one etched into his very bones...