Formerly the prologue of the first version Seishin, also called a "pilot chapter". The story is set in the Tsuge district (柘植町, tsugemachi) of northeastern Iga Province. It is the 10th year of Eiroku (1567); the Tōdai-ji temple was destroyed at the time, escalating the tensions between Nobunaga (Tokugawa's ally) and the priests of Omi Province. Shoutarou enters the premises of Tsuge Castle, and notices many dead bodies. He finds out that is it caused by a vicious oni and is attacked himself. Slowly awakening from unconsciousness, Shoutaro hears the familiar voices of his rival and his parent exchanging angry words.
- Main character. A young Iga who investigates Tsuge Castle and comes across the Mori Oni. Member of Tsukimori Family.
- A young Koga who seems to have a connection with the Mori Oni, and instigates blame on the Iga. Member of Kousaka Family.
- Mori Oni
- (森鬼; forest demon) A gruesome monster that hunted Iga ninja in the northern forests when the Sawamura and Tsukimori families reside, thus its name. In the story, it severely wounds Shoutarou.
- Aina Tsukimori
- Shoutaro's mother. Although she is tender-hearted, she shows an anger towards the Koga.
- (谷丸; b.1547) A peasant Koga ninja who looks up to Kyoushirou. Junior of Kyoushirou; he was killed by Aina.
This article contains information that is recently revealed in either published OR pre-published content. The latter means that the author jumps ahead to show the info without integrating it in the story yet.
As this was a part of the old version of Seishin, the Mori Oni was going to play an important role during an Iga-Koga rivalry. The oni was once a young human farmer named Shōya (賞矢; b.1549; H/W: 170 kg/45 kg). Shoya lived in Koga District and wanted to serve the Kōsaka Family under Kyoushirou, but he was too sick. Regardless, he had a determined character; Kyou sometimes berates his stubbornness. Eventually, Shoya dies; because he was so vain, his body turned into a monster.