After a battle with Mao and the Arm of Kannon, Ryo Kanmu gets sent back 700 years in the past with his right arm infected by the Arm of Kannon. He wakes up after seven years of unconsciousness and finds the power in his arm confined by the Ofuda given by monk Daikaku. The leader of the Nobushi warriors and Lord of Akasaka Castle, Mikami-Danjo, discovers that Ryo Kanmu possesses the powers of the arm and plans to get Ryo on his side to conquer the country.

Mao Mikami
A teenage boy who learns his father has unlocked a mystical evil force that threatens to destroy their whole family. Possessed by some kind of evil, Mao is kidnapped by a secret organization for study.

Maya Mikami
Mao's sister.

Juzo Mikami
Mao's father, who had abandoned his family years ago, is a scholar who learned about the Arm of Kannon. Driven by academic curiosity, he quickly becomes overcome with its magic and turned into a demon. Now infected, he returns home to his wife and children.

Isurugi
Trained to defeat the evil that has infected Mao's family, he is at first treated with indignation by Mao and his sister. But before too long, as the evil that he warns them of begins to appear, Juzo finds himself locked in bitter conflict with an evil organization that wants to study Mao in the development of super soldier beasts.

Masakazu Yamaguchi
Although he made his manga debut in the pages of Shonen Champion, he is best known for the titles he created for Young Jump magazines: Taiyo ga Ippai, Hard-boiled Papa, and BOiNG. His most recent work is Mystery Minzoku Gakusha Yakumo Itsuki.