Breathless Mahoney: The side I'm always on: Mine.
This trope occurs when a particular character's allegiance 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.
- Zeke Yeager in Attack on Titan, who claims what his allegiance is but his actions are very contradictory and he may be a case of Playing Both Sides.
- 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). It's eventually revealed that Gin had been waiting for the perfect moment to kill Aizen for over 100 years for mysterious reasons that appear to have involved his Childhood Friend Rangiku. Unfortunately, Aizen had known all along what Gin had been planning. Gin did pull it off better than Aizen expected, but Aizen prevailed in the end.
- Severus Snape from the Harry Potter books. He repeatedly behaves suspiciously in a way that makes Harry suspect he's working for Voldemort, but others always claim that he's loyal to Dumbledore and working against Voldemort. This is seemingly resolved in the 6th book, but it is eventually revealed that really was working against Voldemort and was motivated by love for Harry's mother (hence the reason he hated Harry so much; Harry looks a lot like his father, who himself bullied Snape mercilessly). Even Snape's seeming betrayal of Dumbledore was done on his orders. Harry names one of his sons after him and describes him as "the bravest man I ever knew".
- Up until The Reveal, no one knew the allegiance of Verin Mathwin from The Wheel of Time. The fact that several key conversations of hers were offscreen, and that she was a Space Cadet of the highest order did not help in the slightest.
- The Golden Company in A Song of Ice and Fire has an unusual take on this — it is pretty clear that they hold allegiance to Aegon Targaryen, also known as Young Griff, but because of their history it is unclear if they've firmly switched to supporting a Targaryen claimant to the Iron Throne in order to get home or if at least elements in the Golden Company think Young Griff isn't actually Aegon Targaryen and has some Blackfyre connection.
- 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, he was slowly dying and needed The Cup of Ankh to save himself.
- This is the raison d'etre of the Alpha Legion in Warhammer 40,000. Officially they're a Traitor Legion, fighting against the Imperium, but the background material — which is deliberately confusing and contradictory, as befits the masters of deception — suggests that they may actually be loyal to the Emperor while despising what the Imperium has become, or possibly loyal to humanity itself, or possibly just playing a long game against the Chaos Gods. Or they may have lost sight of their original purpose and been wholly corrupted. Further confusing matters is their identical twin leaders, at least one of whom is dead, and at least one of whom was probably loyal to the Emperor.
- 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.
- One of the biggest mysteries of the Trails Series is finding out whose side Lechter Arundel is on. In public, he's the secretary of Chancellor Giliath Osborne but in other cases, he also has relationships to Osborne's biggest rival, Olivert and the crown princess of a different country plus working together with an agent of a rival country at a different state in Western Zemuria. And then there's the mystery as to whether he's part of Ouroboros or not as he talks just like the 4th Anguis. This is finally revealed in Cold Steel III and his true allegiance lies with Osborne to atone for the sins his father had caused.