The pink haired, eldest of the 3 Chou Sisters (chou san shimai)

Anime Version

The eldest of three sisters who are trying to make a living by trying out all sorts of show talents, but don't make headway until Kankitsu gives them "magical microphones" that actually broadcast their voices, and become popular idol singers in their town. Ryuubi becomes one of their huge fans.

Visual Novel Version

The eldest sister of the Chō sisters. She and her sisters are a famous idol group and the leaders of the Yellow Turban Rebels in the sequel, Shin Koihime Musō. After being conquered by the Gi faction, she and her sisters join forces with them.

(wikipedia.org)