5-nin no Ou

There are five kings carrying the blood of a god who govern a land called Chevron. Seiji, who has no relatives except his young sister who carries a godly power of reading the stars, agrees to devote himself to the arrogant and ruthless Blue King, Azure. However, by chance he meets the gentle and caring Red King, Gules. He is healed by his gentleness and slowly falls in love with him. But the Blue King does not forgive the thoughts of Seiji, who is still his property. As if to ridicule him, Azure starts toying with his emotions. (Source: Frontier Works, translated)