Rogue Drone

The Hive Mind's version of a Heel Face Turn (or Face Heel Turn) Turn. One problem with writing the members of the Hive Mind is that it leaves little room for individual characterisation since everyone pretty much acts the same way (their personalities being subordinated to the greater whole). Enter the rogue drone, a member of the hive whose mind has somehow broken off of the central entity, opening up the path for him to become an unique character on his own right.

Rarely does the drone itself choose to be that way, though. It may be that the drone has displayed "odd" behavior even before their change, and a rare few may even have developed individuality on their own. Most of them, however, are simply victims of circumstance, who were genuinely faithful and devoted servants up until the point when enemy influence or an unfortunate disaster disconnected them from the central core. For most drones, this is a life-shattering event. Most of them do not have a natural concept of individuality, and without a higher authority to make decisions for them they become lost and confused. A lot of them attempt to rejoin their hive, only to be driven away because Individuality Is Illegal.

Many feel incapacitated and insignificant on their own. Human social hierarchy can work as a substitute, and many of them end up joining the main cast as the Token Heroic Orc. Developing a personality is both a challenge and a source of anguish (as it removes them even further from their peers). Choosing a name is often depicted as one of the first milestones they need to conquer. Expect them to still go on long rants about how individuality is incomparable to the satisfaction of being part of a greater whole. They are often subject to the the Pinocchio Syndrome as they are trying to understand human customs and thinking.

It should be noted that while in most cases the Hive Mind is depicted as "evil" and the rogue unit as "good", this is sometimes reversed. Deserters from a good overmind tend to be a lot more powerful and destructive, undermining their own hive from within abusing the fact that the hive does not expect its members to turn on each other.

A variant of My Species Doth Protest Too Much. Compare the Phlebotinum Rebel.

Comic Books

 * Scud the Disposable Assassin. He was programmed to take down his target and self-destruct, but a glitch in his programming gave him a will to live.
 * Quislet of the Legion of Super-Heroes is an escapee from his universe's hive mind.
 * Scar, the rogue member of the Guardians from Green Lantern. A physical disfiguration - a scar on his face by an enemy - is what triggers her deviation from the rest of her race. (Two other members, Ganthet and Sayid would later also take names, with far more heroic results.)

Film

 * Agent Smith in The Matrix - originally a guardian AI in a simulated reality, he becomes something akin to a computer virus.
 * Sonny in the I Robot movie.

Literature

 * Lady Myria LeJean, from Terry Pratchett's Thief of Time. The Auditors aren't technically a hivemind; they're separate existences that don't allow individuality, though, so it's much the same effect. Once she picks up a physical body, a name, and a gender, she starts seeing life as less of a blight on the perfection of the universe.
 * The surviving clone in Ursula K. Le Guin's short story "Nine Lives." The story is about his attempt to come to terms with being an individual after the rest of his clones are killed (the clones having been bred and raised as a functional Hive Mind).
 * The author of the Metabarons Universe have another series in which an accident in the police officer-cloning factory results in one clone being a giant. He only wants to serve like the others, but the system perceives him as a threat and tries to kill him, so he ends up joining La Résistance.
 * Mark from the Vorkosigan Saga might count. He's a  who manages to escape his programming, and become (mostly) a good guy.
 * Played interestingly in the Codex Alera with the Vord, where it's one of their Hive Queens who starts developing her own personality (leading the other queens to try to kill her to prevent her from "infecting" the rest of their race). Arguably deconstructed in that she stays a villain even while developing increasingly humanlike personality traits
 * In Lifelode by Jo Walton, Hanethe spent some time as part of the goddess Agdisdis, whom she spends most of the book trying to escape due to a disagreement with the remainder of the goddess that led to Hanethe thwarting Agdisdis's plan.
 * of The Madness Season is such, at least during those times when he is not connected to the Tyr hive mind.
 * In the later books in the Ender's Game series, it's hinted that  This has not been developed, but may be a plot thread for later books.

Live-Action TV

 * Hugh the Borg in the Star Trek the Next Generation episode "I Borg".
 * Seven of Nine from Star Trek Voyager (whose full designation is 'Seven of Nine, Tertiary Adjunct of Unimatrix Zero-One'), a human assimilated at an early age by the show's antagonistic Hive Mind, The Borg. After her link to the collective is severed, she struggles with her rediscovered humanity.
 * Unimatrix Zero is a subcollective of drones who retain their individuality and can communicate when regenerating, who are eventually severed from collective control and start a civil war within the Borg in the finale of season 6. Seven of Nine was a member of Unimatrix Zero before being freed from the collective.

Tabletop Games

 * Archangel Entertainment's game Zero starts off with PCs who are suddenly separated from their Hive Mind ("The Equanimity", which is under the control of "Queen Zero") and become individuals. Not only must they survive without the help of the rest of the Equanimity, they are actually hunted by it on the orders of Queen Zero.

Video Games

 * Nordom from Planescape Torment. In the Planescape Dungeons and Dragons setting, Modrons are a race of pure law, from the pure Lawful Neutral plane of Mechanus. They're rather robotic in their behavior, but those that experience a "glitch" in their "programming" (often caused via Logic Bomb) become rogue modrons and gain some independence. The Modron share lifeforce (whenever one dies, one of each rank below is promoted to fill the chain of command and one bottom rank modron is produced) so any discovered rebels get... recycled(this seems to be handwaved in the computer version - you can talk to other modron with Nordom in tow and they won't turn hostile). The first time the player encounters Nordom, the protagonist casually refers to him as a "backwards Modron", thus accidentally giving him a name allowing him to think of himself as an individual.
 * Player Character from Quake IV could be called an example of this trope, although it is more of a case of a person never fully turned into a hive member in the first place.
 * Mass Effect 2 plays with this trope. Legion is not a single drone but a cluster of 1,183 Geth runtimes, but they co-inhabit a single (very durable) combat platform and the nature of their mission makes contact with the main Geth Hive Mind very sparse. They are not actually "rogue" but more like "on a permanent deep-cover mission, maintaining radio silence at all times" - it turns out that the geth Shepard has been fighting are a "heretic" splinter faction, and the majority of the geth want no more to do with the villains than Shepard, who Legion was specially sent to assist.
 * from Dragon Age Awakening was born unable to hear the song of the Old Gods, and thus possessing free will (unlike other darkspawn). He discovers a way to make other darkspawn into Rogue Drones as well, though this...doesn't always go well.

Western Animation

 * Brainiac-5 from Legion of Super Heroes. "Fear Factory" reveals that his biggest fear is being forced back into the Hive Mind.