Gao Ta Zhong De Ye Shou

Leigh travels to the royal capital in search of his father’s whereabouts and is introduced by the headmaster to a job as a royal tutor. What he doesn't expect was that Prince Potter is a barbaric half-beast imprisoned in a tower who can't even speak human languages. Unable to leave the tower, Leigh is locked up inside and tasked with teaching the Prince courses according to the instructions and objects that come through the door...

(Source: WebComics)

Note: Chapter count includes 3 extras.