Shizuka Usui

"'I'm sorry for the late introduction, Yuki-sama. My name is Shizuka Usui.'"Shizuka Usui is one of the 'masters' who taught the Zweilts. He is the teacher of Tsukumo and Touko Murasame. He is the elder cousin of Shuusei and notable looks quite like him. He first appears in story 48.