Shiina Mayuri, also known as Mayushii☆, is Rintaro Okabe's childhood friend, a part-time worker at MayQueen+Nyan².
She is a fan of cute things, like the Upas from the in-universe RaiNet Kakeru series, an avid cosplay maker and a friend of Luka Urushibara and Faris NyanNyan.
Has horrible luck with her pocket watch working properly.