Fallen Moon(2004)

Daten no Tsuki

A young man, Rukis, has left Eden and wanders the desert until he collapses and awakens in a strange mansion. There he meets the master of the house who has rescued him. Rukis reveals the true reason for why he was thrown out of Eden and learns that the master of the house may share a similar past. As the two open up to each other, Rukis and the master begin to develop a steamy relationship.

(Source: BLU Manga)