Dong Gong Jie Xia Qiu

The day his country perished, the once mighty monarch fell into the hands of the enemy crown prince, who brought him back to the Eastern Palace with the unexpected intention to enslave him since. The fallen monarch thought the life of a prisoner meant nothing but sheer darkness, yet to his surprise, in spite of receiving angry insults from the brooding prince, he enjoys the prince's tolerance and the privileges that come with it. "What did the prince mean when he mentioned the past we share? Umm… Why do I seem to have no recollection of whatever happened at all…?"

(source: Webcomics)