Rika Ishikawa
Def.Diva (often stylized as DEF.DIVA) was a "special group" formed in 2005 from the Hello! Project idol umbrella, and consisted of Aya Matsuura, Maki Goto, Natsumi Abe and Rika Ishikawa. The band's name is an abbreviation of the phrase "Definite Diva".