Haizaki Mejiro

Hector is a demon descended from a clan of doctors who made their living researching diseases deep in the bowels of the underworld. As a child, he falls in love with Lord Vet after the demon prince saves him from a group of bullies. A faint trace of that love lingers as he grows to maturity. One day, after being bitten by a stray zombie dog, Lord Vet contracts an incurable disease known as "The Black Scourge". Hector is assigned as Lord Vet's personal physician, but the prince's heart is deeply wounded, and he demands "comfort"…!

Tsubakimaru is a human half demon, in the middle of a trip where he is a prisoner they enter a strange mountain where there are no animals and vegetation and there he meets the God Shii who carries a fearsome curse…