Was once a young boy called Yasuo, ill and sickly when born. He was the firstborn in his family, but his parents were ashamed of him. His brother was born healthy, and thus became the favourite of his parents. Jealous Yasuo wanted that attention and yearned for love, and despite their parents trying to prevent it, his brother didn't see why they had to leave Yasuo all alone. He would tell Yasuo about stories of youkai, and Yasuo wished he could be a youkai so he could have power over his parents.

Things came to a head when Yasuo tried to sneak out one day and was caught by his father, who in his rage accidentally strangled him to near death. Afraid of being called a murderer, he buried his son under the house. A kitsune possessing a woman happened to pass by, being chased by villagers, and saw the dying child; seizing the opportunity, the kitsune possessed him instead and brought him back to life as a kitsunetsuki.

The dead child is no more than a revenant, vengeful and seeking to wreck havoc on all those who have what he didn't have in life. He has taken on the name of his brother, the only person who cared for him, and is prepared to do whatever it takes to soothe his rage. Even if it corrupts his heart and slowly turns him into something worse...