Arm of Kannon - Masakazu Yamaguchi

Mao suffers from nightmares. But these nightmares may reflect a horror that will soon manifest itself in his reality. On the way to school with his sister Mayo, Mao meets a mysterious stranger from Mr. Isurugi who claims he was sent by their father to be their body guard against an unknown evil. Three years ago, Mao and Mayo's father, the archeologist Juzo Mikami, disappeared on an expedition to discover the legendary Arm of Kannon. Now, as a bewildered Mao returns home from school, he finds his father there, seemingly scarred, both physically and emotionally. Before too long, Mao learns the horrible truth that Isurugi's arrival prophesied. Juzo's discovery has unlocked an evil within him, an evil sought after by a secret organization working with the military who wants to harness the power of the Arm of Kannon to create super soldiers. When Mayo returns home a few hours later, she finds a frantic Isurugi holding a sword over the body of her brother, claiming that the boy has now been possessed by a demon. But before he can harm the child, the military shows up to take Mao to their secret laboratory as a study subject for their experiments.;But Isurugi won't let Mao or Mayo go without a fight, challenging the military's muscle, Shishio, to a duel.