A woman who has influence within Shiba. She appears to know Ryoko on a personal basis. She is also the true head of the Japan Private Police. Ruriko is seemingly ageless, having been alive after through World War II and was a co-founder of the Japanese Empire Security Service with Ryoko's grandfather Masamoto Yakushiji before she diverged and created JPP originally with the intent of reestablish a true Japanese military using a security company as a cover.   

Based on a series of light novels written by Tanaka Yoshiki and illustrated by Kakinouchi Narumi. 
The story revolves around Ryouko Yakushiji, a 27-year-old multilingual investigator that graduated from Tokyo University's elite Department of Law, and the bizarre cases she faces while working for the Tokyo Metropolitan Police. Yakushiji not only has to deal with supernatural beings in her line of work, but also her rival Yukiko Muromachi, another equally talented and beautiful police investigator. 
(Source: AniDB)

[Website (WMG)](https://wmg.jp/shimamotosumi/) | [Wiki (JP)](https://ja.wikipedia.org/wiki/%E5%B3%B6%E6%9C%AC%E9%A0%88%E7%BE%8E)

A Japanese actress, voice actress and narrator of film, anime and video games. She is currently independent of any talent management company.

After graduating from the Toho Gakuen College of Drama and Music, she joined Gekidan Seinenza, a theatrical acting troupe. Her best-known voice roles include [Nausicaä](https://anilist.co/character/539/) in [Nausicaä of the Valley of the Wind](https://anilist.co/anime/572/), and [Kyouko Otonashi](https://anilist.co/character/4745/) in [Maison Ikkoku](https://anilist.co/anime/1453/).

She won the role of Nausicaä as she had played [Clarisse](https://anilist.co/character/11236/) in [The Castle of Cagliostro](https://anilist.co/anime/1430/) and impressed Hayao Miyazaki.

She is married to Daisuke Koshikawa, one of the founders of the comedy troupe Chibikko Gang. Their first child, [Shiori Koshikawa](https://anilist.co/staff/185752/Koshikawa-Shiori), has also done voice acting.

(Source: Wikipedia)

The story revolves around Ryouko Yakushiji, a brilliant 27-year-old elite investigator with the Tokyo Metropolitan Police. Together with her subordinate Junichirou Izumida, the two often investigate bizzare and supernatural cases. In addition with the paranormal, Ryouko also has a longstanding rivalry with Yukiko Muromachi, another talented police investigator. 
(Source: Anime News Network)

Isurugi Ruriko