In most series, either Everyone Is Bi or there are No Bisexuals; there's usually not much room in between. However, there is one group of bisexuals who seem all too well represented in the mainstream: the cold-blooded murderous sociopaths. Interestingly enough, though, many if not most Lesbian Vampires are in fact bisexual. Fan Service, you know. Contrast Bi the Way, where the character just happens to be attracted to men and women without being so... extreme; and Anything That Moves, where the bisexual/pansexual character just happens to be also hypersexual.