Seinaru Kishi no Ankokudou

Young Sain Forth has it made; as the famed Holy Knight, he has the people's love, the respect of kings, and the blessings of a literal goddess. His aspirations lie elsewhere, though. With his assistant Melia at his side, he leaves for an academy in a foreign kingdom, where he is treated as a deviant by his peers. It's his own fault, mind you—his stubborn insistence on wearing a custom, all-black uniform makes him stick out.