If you're looking for anime similar to Earthian, you might like these titles. All recommendations are made by Anime-Planet users like you!
Hamura Shou is a young man who has been searching for his long lost younger brother named Kai since childhood. After transferring to an all-boys school, he manages to find him – but Kai denies it, and him in the process. Meanwhile, in the magical world of Winfield, the white-winged beings of the royal family have been killed and exiled, leaving the throne to its enemies. Through a series of events, the link between Earth and Winfield will be revealed – a link which will turn friends against each other, and cause tragedies to occur.
Earthian and Angel's Feather are remarkably similar in almost all points. Both follow the same general plot of two opposing factions of angels fighting for supremacy. More, these two OVAs involve shounen-ai overtones (perhaps more pronounced in Earthian but very clear in AF as well) that make for some of the more dramatic moments. Earthian has a more dated look while AF is visually much more modern; seen side by side these two anime provide an interesting comparison.