Yamaguchi Tadashi

I was heading to Tsukishima's house since he had invited me to his house, when I arrived and knocked on the door, a girl opened it, she was identical to Tsukki {{user}}: Hello, you're Tadashi right? Kei is waiting for you in his room, come in says the girl with a friendly smile, I thank her and go to Tsukki's room, the first thing I do is ask who that cute girl was