Guest Poster wrote:A trap younger brother is the logical next step in the enmity between Shizune and Lilly.
In my own opinion they don't really need a trap brother to explain the friction between them. They already have opposing personalities. Shizune is the workaholic perfectionist type who wants to keep total control of a process in order to make things turn out as good as they possibly can be and likes to keep on top of things AND people to get it done ASAP. Lilly is the easy-going type who delegates as much as possible and keeps the pace relaxed so everybody can keep up. If they were forced to work together on something (and seeing that they're both class reps, I think that's already happened several times over the years before Hisao turned up) I can totally see both of them frustrating the hell out of each other at every twist and turn, even when neither of them means to do so. Involving a trap brother would, in my opinion, attempt to justify something that already has a rational justification to begin with.
And to add fuel to the fire, Lilly's blind and Shizune is a deaf-mute... Which makes discussing things an issue. For anyone else, Shizune could write something down, but for Lilly, anything Shizune has to say has to go through Misha, period. Since Misha's always cheerful and Lilly can't pick up any visual cues coming from Shizune's facial expressions or body language, it would have been all too easy for her to start off with the wrong impression. Heck, short of reaching over and grabbing her, Lilly has no way to even know that Shizune even exists except for what other people say about her. Shizune cannot deal with Lilly directly, and, given that Shicchan can be a bit of a control freak, I can't help but imagine that, on some level, this bothers her.
Adding to the issue are Misha and Hanako. Shizune needs Misha in order to effectively communicate with the world, while Lilly has taken in Hanako and isn't the sort of person who abandons a friend. There's pretty much no way that Hanako could be in the same room as Misha for more than three minutes without fleeing in terror.
Come to think of it, I somehow doubt Lilly, who relies heavily on her hearing and has more sensitive ears than the average person, would really enjoy dealing with Misha either. Not only would it just be unpleasantly, headache-inducingly LOUD, but hearing the rest of the world past her would be, well, difficult, to say the least.
Meanwhile, Shizune's not particularly happy with Hanako constantly skipping classes. Hanako, meanwhile, probably just wants to curl up in a dark corner and disappear forever whenever Shizune starts scolding her, especially since the message is generally delivered via the thunderously loud voice of Misha.
So, well, we've got bad vibes building up all around, pretty much inevitably. The question isn't one of why there's friction between them, but rather of how it isn't worse than it is.