Shinno is the Osa of the West, presiding over the youkai and monsters in the western territories of Japan from his home, the floating Takachiho Mansion. He is much younger than the Osa of the East, and arrogant as he believed his creations, the Maduchi, would enable him and his minions to defeat Hakumen no Mono. He tried to enlist the Eastern Yokai but they refused, and tried to convince Shinno to have faith in the Beast Spear's Chosen One, Ushio Aotsuki. Shinno refused to even consider putting their faith in a human and when the Eastern Yokai attacked, Shinno and his duisciples, using the maduchi, repelled them and kidnapped the Eastern Osa.

When at last Shinno and his army faced Hakumen, he realized even sealed up, Hakumen was beyond their power to defeat, even with the Maduchi. Seeing how his rash actions had cost him many of his subordinates' lives, Shinno at last allied with the Eastern Osa and placed his trust in Ushio and Tora.

He wields a powerful sword named Rubashiri.