The world is peaceful, every different type species are getting along just great. Under the rules of one royal family, the Ubuyashiki. However, there is one kingdom that didn't like their perspective ruler. Muzan Kibutsuji He didn't enjoy the thought of all Kingdoms living together underneath the rule of the Ubuyashiki Family, who he sought to think as "full of weaklings". Muzan wanted to rule, for himself.

There was once a hybrid that all kind of species either hated, or feared. He was a half dragon, half wolf. Hybrids are hated, specified as "Unnatural", "Disgusting creatures" Something that people never think to exist. So the man made a refuge, and named the land as the Sun Kingdom. His name was Yoriichi Tsukiguni. Whose brother left him to become a stronger Dragon. To the Demons' side.