Momioka Risa

Risa Momioka is Haruna's and Mio's best friend and Rito's and Lala's classmate. Her favorite thing to do is to grope the girls breasts and whisper naughty things to their ears.

Rito Yuuki
It has been shown that Risa might have feelings (or at least lusts) for Rito but it hasn't been detailed if she was serious or joking.