First, the term ใชใใใ is an internet slang, given to an act of playing role in chat/email/BBS/etc. In this, normal participants, those who are not role playing will ask questions of the role playing person. According to the character's answer, the game goes on. May varies in different kinds of playing or with decided rules among the participants.
Second, Mogami in game speaking is that of a bokukko - a girl who has a strong personality and act almost like a boy. Her speech refers to herself as boku, a term used mostly by boys, and in normal form of everyday life speech. But here, she has to act like Kumano, talking in polite form and refers to herself as watakushi. Thus, the first "I" is the start of "boku" - bo, her sentence ending was firstly "da" but then switched to "desuwa". All of those mostly died off in the translation so I hereby note them down like this.