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.

Lala Satalin Deviluke
She is good friends with Lala and likes groping her breast.

Mio Sawada
Risa's friend, she also enjoys groping girls breast and whispering in their ears.

Haruna Sairenji
Risa's friend who occasionally gropes Haruna, sometimes saying they've "grown"