This game is based on the anime Ikki Tousen (一騎当千 Ikkitōsen, lit. "Strength of a Thousand"), known in North America as Battle Vixens, also a manga series written and illustrated by Yuji Shiozaki, based on the classic Chinese novel Romance of the Three Kingdoms. The series revolves around an all-out turf war in the Kanto region of Japan where fighters known as Tōshi (闘士), meaning "fighting soldier," from seven schools battle for supremacy. The story centers on Hakufu Sonsaku, a fighter who transfers to Nanyo Academy, one of the seven schools involved in the turf war.
A video game of the series, Ikki Tousen: Shining Dragon (一騎当千 Shining Dragon Ikkitōsen Shainingu Doragon), was developed by Idea Factory and released for the PlayStation 2 in Japan on July 26, 2007 by Marvelous Entertainment. The game has an original storyline with Hakufu, Ryomou, and Kanu as the main playable characters. The game introduces a new character named Chousen, the Japanese counterpart of Diao Chan. Along with Hakufu, Ryomou, and Kanu, Gentoku Ryubi, Ukitsu, Ekitoku Chouhi, Shiryu Cho-n, Housen Ryofu, and Myosai Kakouen also appear as playable characters, with Koukin Shuyu appearing as an extra character in Hakufu and Ryomou's story arcs respectively.
Source: Wikipedia, "Battle Vixens", available under the CC-BY-SA License.