An information trader nicknamed 'the devil's ear' who becomes friends with Naoe when he is Kasahara. After his wife dies, he takes Akiko, a former hostess, as his common-law wife. He also knows Sasaki, Irobe Katsunaga's former incarnation.

In the current era, he lives in Tokyo with his son and his son's wife, and meets Naoe again while Naoe is searching for Takaya.

Although retired, he introduces Naoe to his protégé Kuroki.

Musashi Province, a province of ancient Japan, was comprised of the present-day prefecture of Tokyo as well as parts of Saitama Prefecture and Kanagawa Prefecture. It was the largest province in the Kantou and was formed in the 7th century. It was governed by many, many clans, including the original Houjou Clan for about 100 years starting from the 1210s. The Later Houjou Clan took the territory in the late Sengoku Era after the Battle of Kawagoe Castle in 1546 drove out the Uesugi influence. Tokugawa Ieyasu took control of the Kantou after the fall of the Houjou Clan in 1590.

A young man who befriends Takaya while backpacking in Iya. He lost his memories after falling off a cliff five years ago. His name was given him by the doctor who treated his amnesia, Dr. Mutou. His first name, Ushio, means "ocean tide". He likes photography and fishing, and is friendly and outgoing.

Takaya recognizes that he is kanshousha, and because of that he is hounded by the Tosa Red Whales to join their group.

Also known as: Oushuu (奥州)

The largest province of ancient Japan, situated in northern Honshuu, which was ruled by various clans during the Sengoku, including the Uesugi, Nambu, and Date. It was divided into the prefectures of Fukushima, Miyagi, Iwate, and Aomori.