Ambiguous Allegiance

This trope occurs when a particular characters alleigance is so unclear as to be a prominent subject of debate among fans. No one is ever really sure who this character is loyal to or if they even have loyalty to anyone. Many things may cause this: Perhaps there's reason to think that the character may not be in control of their own actions, or perhaps they simply change sides as often as you change clothes. Either way, you'll be left wondering whose side they're on for a while. The question may eventually be resolved or it may simply left up to the fans to debate.

Anime and Manga

 * In Bleach, Gin's allegiance was in question a lot (at first he seemed to be the Obviously Evil Big Bad, then he was revealed as Aizen's minion in a Double Subversion, but in the scenes where he appeared in Las Noches he still seemed rather untrustworthy). Finally it's revealed that.

Literature

 * Severus Snape from the Harry Potter books.

Live Action TV

 * Jason Winkler from House of Anubis was a good guy at first, and then he started to unravel the mystery of Joy Mercer's disappearance. Ultimately, this led him to Victor and the next thing the viewers knew, he had joined Victor's society. This spawned some debate among fans of the series as to whether Jason was being forced to cooperate with the society or whether he had joined of his own free will. (A third theory is that he is the Reverse Mole, pretending to be loyal to the society in order to gather information on them.) Turned out,

Video Games

 * Axel from the Kingdom Hearts series has no doubt been the subject of such a discussion at least once. Not even his fellow Organization members are entirely sure of where his loyalties lie.

Western Animation

 * Mr. Krabs from SpongeBob SquarePants