Ryuu no Yuigon (Yaoi)

The following content is intended for mature audiences and may contain sexual themes, gore, violence and/or strong language. Discretion is advised. Half-dragon, half-human Asagi is sworn to protect the demon-lord Tenran-sama ever since birth. What makes things difficult is that said Tenran-sama turns out to be a boyish-looking blonde who exercises a great deal of time and effort in getting Asagi to sleep with him. Not to mention the number of rivals who are looking to steal Tenran's immense powers. (Source: Yaoi Manga Recs)