Rinami is cosplaying as Arashiko Yuno from MM!. MM! is a Japanese light novel series by Akinari Matsuno, with illustrations by QP:flapper. Twelve novels were published by Media Factory under their MF Bunko J imprint between February 2007 and September 2010, including two side story volumes.
Yuno is Taro Sado's classmate. She has androphobia due to an attempted sexual assault by her former boyfriend in junior high school, and will attack any males who touch her, subconsciously feeling that she has to hit them before they hit her. She is also the one who caused Taro to become a masochist but despite her androphobia she develops a crush on Taro and is also hinted to be jealous as well when another girl is involved with Taro.
She occasionally gets into situations where she briefly forgets her androphobia in her eagerness to get closer to Taro (or is accidentally touched by him), and when she actually realizes what happens, she comically assaults Taro who, due to his masochism, enjoys it.