In the NSFW story King of MolMol, Kanako Urashima apparently knows how every girl fits into the harem genre.
Kanako: "Don’t you know how harems work? There are specific roles the girls fall into. You are the loli housewife."
Shinobu: "W-What about the rest of you then?"
Kanako: "Well I'm the little sister, Mutsumi's the ditz who ends up getting hurt but somehow survives, Kitsune is flirty prankster, Tsuruko is the sadistic/masochistic shrine maiden, Motoko is stoic warrior who's really a slut, and Naru’s the tsundere."
Shinobu: "Then what about Su and her family?"
Kanako: "Su would be the crazy genius, Amalla the mysterious foreigner, Asuna's the slut that's always trying to get at Onii-san's dick and Nina is the foreigner that doesn't speak Japanese well and misunderstands what is going on with comedic results."