Slave Emperor

Claren, the half-breed princess of the barbarians. She has been weak since childhood and cannot walk, so she is ignored even by her servants, and is eventually abandoned by her family during the war with the barbarian nation of Kailom. In revenge, she handed over the entire royal family to Kailom, and was given a title in recognition of her achievements. When Claren raised her head with the king's permission, Dean, the runaway slave, was standing there.

(Source: Ridibooks, translated)