Higashi no Watatsumi Minami no Soukai

A kirin named Rokuta from the En Kingdom was sent to Japan as an infant for safety but was soon abandoned by his foster parents and left to survive in the mountains. Around the same time, a boy named Koya was also abandoned in the En Kingdom and taken in by demon beasts. The two boys share a similar fate, and twenty years later, their paths cross, possibly leading to dire outcomes for the En Kingdom.