A thousand years ago, demons ruled over the lands in tyranny. They trampled on other races, especially humans, and used them as mere objects to satisfy their needs. Among many demon clans, three of them opposed their own kind and protected the humans from harm. One of those clans is the Kusakabe. One night, an ambush happened in Yokowara where the Kusakabes resided. Seeing as there were no other options, the head of the clan, Ryuugon performed a spell to seal his youngest child, Ryuuji, and sent him far away to an untouched land. When he wakes up, Ryuuji realises he is now in a different place with unfamiliar faces, a thousand years later.