The archeologist Tozo Mikami discovers an ancient Buddhist relic, The Arm of Kannon, an object of strange and mystical power. But soon afterward, he disappears, leaving behind a wife and two children. Three years later he reappears ... but he may not be the man he was. His son, Mao, suspects the worst. And when a mysterious warrior shows up as a protector for he and his sister, Mao begins piecing together the story that may lead to a secret organization committed to exploiting the magic of the ancient relic for the development of super soldiers for the military.

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.