• Family Name: Yagyu
• Surname: Nasuti
• Alias: None
• Ronin Warriors Alias: Mia Koji
• Also Known As: "Nasti" or "Nasty"
• Attribute: None
• Ronin Warriors Attribute: None
• Born: May 28, 1970, somwhere in France (Paris?)
• Height: 5 feet, 6 inches (1.68 metres)
• Weight: 120 pounds
• Blood Type: AB

Touma says: "When Arago first attacked the Earth Realm, he made a critical error: he left Nasuti Yagyu alive. Out of everybody on the entire planet, she must be the foremost expert when it comes to all things related to Arago or the Dynasty - she and her (now deceased)grandfather had been researching the legend of our yoroi for years, and she knows things about them that even we don't! She and Jun Yamano wound up travelling with us and supporting the Samurai Troopers in our battle against Arago and the Masho. In addition to her usually vital information, Nasuti also provided us with transportation -in the form of her car, a 1988 Suzuki Samurai- and a base of operations in the form of her house, a lovely little mansion in the Kanagawa Prefecture. She also owns a second house and a boat dock on the shores of the Yamanaka Lake. As you may have guessed, the Yagyu family is somewhat wealthy, which is a good thing; having to buy groceries for Shuu alone would have bankrupted most people!

Nasuti Yagyu was the de facto "den mother" for the Samurai Troopers, providing them with food, shelter, and information while they battled against Arago. All of the Troopers view her as the big sister they never had, and love her dearly. She also serves as a mother figure, looking after Jun and keeping the Troopers in line when they begin to misbehave. Although her family has been in Japan for generations, Nasuti was born and raised in France, and moved to Tokyo only recently. Among her other skills, Nasuti speaks fluent French, English, and Japanese, all with no discernable accent. Although not a very good fighter, she has begun training in the use of the naginata.

Nasuti Yagyu's japanese voice actor, or seiyuu, was Kaori Kusakabe. There is currently no available information on other roles performed by Kaori Kusakabe.

In the Ronin Warriors dub, "Mia" is voiced by Lalania Lindjberg.. She is also known for her roles as Venus De Milo in Ninja Turtles: The Next Mutation, Alice Sakaguchi in Please Save My Earth, Natsume in Ranma 1/2, and Bulma in Dragon Ball, Dragon Ball Z, Dragon Ball Z: The Dead Zone, and Dragon Ball Z: The World's Strongest.

Mia was also voiced briefly by Teryl Rothery, best known for her role as Kodachi Kuno in Ranma 1/2. Teryl is also known for her role as Eiko Megami/A-Ko in the Project A-Ko series and as the doctor on Stargate: SG-1.