Mari

Mari is B-ko's muscle! First seen when sicced on C-ko so that B could rescue her, she took too long to run there so A-ko did it instead.

Mari has a beautiful voice.

Mari stands at least eight feet tall with tanned skin and an enormous musculature. She is an obvious parody of Kenshiro from the anime/manga series Fist of the North Star. She looks quite a bit like him, uses a similar fighting style, constantly tatters her clothing when flexing and has many of his mannerisms; however, her speaking voice is a normal female one.
 * Mari voiced by Daisuke Gōri, Sayuri Ikemoto (Japanese)