Warren heard the knock and left Kitty playing the computer game on his computer with her juice box, cause he's a good babysitter like that, to answer. He pulled the door open, thinking by the way the person said his name, that it was Shiro, just... higher pitched?
Ok, that was Shiro's sweater, but it was decidedly a girl. "Hi. Do I... know you?" he smiled pleasantly, leaning against the door frame.