Mind Hive

"Shepard: Then what should I call you?

Legion: Geth.

Shepard: I mean you, specifically.

Legion: We are all geth.

Shepard: What is the individual in front of me called?

Legion: There is no "individual". We are geth. There are currently 1,183 programs active within this platform.

EDI: "My name is Legion, for we are many."

Legion: Christian Bible, the Gospel of Mark, chapter five, verse nine. We acknowledge this as an appropriate metaphor. We are Legion, a terminal of the Geth."

- Mass Effect 2

As Hive Mind is one mind, many bodies, Mind Hive is many minds, one body.

Mind / Consciousness / whatnot of different people are housed within one body, most likely through magical or technological means. The minds can communicate with each other, and normally actions are through consensus.

Distinct from Split Personality because even if what's housed inside is totally separate entities that got merged, they still retain their individuality. Sometimes may speak in I Am Legion pattern. Compare Many Spirits Inside of One. See also Animal Eye Spies.

Anime & Manga

 * In the Fullmetal Alchemist manga, is this, due to being a living Philospher's Stone. He's revealed to have reached an accord with each of the tens of thousand souls sharing his body, though he's the dominant one in control.
 * Envy's true form. He claims the souls lost their personalities long ago, but that doesn't stop faces from popping up all over him and wailing things like "mommy!". They also tend to speak for his subconscious ("Don't look!" "Don't Look!" "At me!"), so there are a lot of reasons he just doesn't wear this form normally.
 * For some reason he also never gets very big otherwise. Maybe because impersonating an elephant isn't especially subtle in Fantasy Germany, and when they have artillery it doesn't give you much of a combat bonus, either. Despite the bent rail he doesn't generally have the impact on his environment that you'd expect from something the size of an elephant...
 * In Hellsing, vampires keep all the souls of the people they've devoured inside them. Alucard had millions of souls.
 * In the Yu-Gi-Oh! Virtual World arc, after Nezbit of the KaibaCorp Big Five managed to take Honda's body, all five of them collectively shared the body in a duel against Yami Yugi and Jonouchi. Although they were able to chat amongst each other to make decisions, they rotated out who was in charge while also rotating deck masters.
 * At the end Saint Beast: Kouin Jojishi Tenshi Tan, there is a monster made up of the angry spirits of purged angels, sharing one giant body of miasma. A similar case occurs earlier with the dead of the lake town.

Comic Books

 * The Kree Supreme Intelligence in Marvel Comics is the collected brains of all the important Kree, harvested upon their deaths.
 * In Zorn & Dirna: Les Laminoirs, Death has been imprisoned and cannot claim any lives. Since people still age and become horrid-looking, necrotic zombie-lookalikes, they are by law forced to go (or be dragged) to facilities where they are beheaded... which won't kill them, but make the soul take residence in the axeman. Some of the axemen (who are usually prisoners) harbour several thousand souls, which can fight for control of the body.

Literature

 * In Glen Cook's Black Company Novels, Soulcatcher (a powerful spellslinger whose primary talent is Exactly What It Says on the Tin), might well be the epitome of this trope.
 * Hohass "Runt" Ekwesh from the X Wing Series is this. He has many minds and they're all different. There's the pilot mind, the pirate mind, the careful mind, the student mind....yea, his entire race is made up of creatures with a different mind for each task.
 * Frank Herbert's Dune series. Abominations are people who experience Bene Gesserit past memory sharing before birth. As a result, they are subject to being taken over by the personalities of their genetic ancestors. This can lead to some interesting situations:
 * Alia was taken over by multiple personalities just before her death. Prior to this, her grandfather had controlled her for a fair amount of time.
 * Leto II reached a compromise: He built a sort of council of more level-headed ancestors (led by an Egyptian Pharaoh) to help him share his consciousness, staving off some of the crazy ones (like ).
 * Robert Heinlein's I Will Fear No Evil. After having his brain transplanted into another person's body, Johann Smith picks up additional personalities: first the one which formerly inhabited his body, and later
 * Altogether Andrews from Discworld. He has several personalities lodging inside his body, some of which are only darkly referred to and never seen. And none of which are named Andrews. The going theory in-universe is that he was a psychic who let in too many wandering spirits, and the spirits eventually crowded him out.
 * Clifford Simak's Time is a Simplest Thing has a psychic power called mindshake. It's a personality exchange.
 * In Gene Wolfe's "The Book of the New Sun", there are several ways this can happen
 * The protagonists of Black Star Rising by Frederik Pohl include a scientist known as Manyface, who once nearly died from brain damage that was treated by replacing the lost sections with pieces from the brain of a dead boy. When asked if he could remember his name, he gave it, then gave the dead boy's name a second later. The two realized that their joined knowledge was a great aid to the scientist's research, and by the start of the story they've collected so many brains they've had to undergo experimental skull-enlargement surgery to fit them all in.
 * Shades in The Inheritance Cycle.
 * In Ekaterina Sedia's The Alchemy of Stone, the soul-smoker is this after a lifetime of absorbing ghosts.

Live Action TV

 * Lexx: Kai has the memories of all those he has assassinated in his service to His Divine Shadow.
 * Dollhouse: By the end of the series, both Echo and Alpha have assimilated dozens of personalities.
 * You may call me Legion, for we are many. "You mean you're a gestalt entity?" "Yes."
 * The Time Lord Matrix in Doctor Who is a computer housing the collected memories of all the deceased presidents of Gallifrey. Unlike the Kree Supreme Intelligence (see Comics), it is not itself sentient, but it is possible to enter it as a virtual reality Cyberspace.
 * Done in Stargate SG-1 and again in Stargate Atlantis; in both cases, the mind hive was created to serve as The Ark.
 * Crusade had one of these as a Monster of the Week. It began to spread parts of itself amongst the crew of the Excalibur, turning each crew-member into a platform for one of its personalities.

Tabletop Games

 * The Synad race from Dungeons and Dragons Complete Psionic handbook.

Video Games
" : We are each a nation."
 * The Geth from Mass Effect are a purely software-based species, and house themselves in massive space-based data hubs that contain millions of Geth programs, all of which communicate and work to build consensus. When the Geth need to fight or perform other necessary tasks, they upload themselves into "mobile platforms" - the Geth soldiers, ships, and vehicles encountered in the games themselves.
 * Interestingly, "individual" Geth programs are non-sapient, being too simple to function beyond their original purpose; this was an intentional limitation placed by the Quarians to avoid creating an AI. However, when the programs are able to network together, they are able to create something greater than the sum of their parts and achieve a unique form of sapience.
 * Then again, in Mass Effect 2, the destruction of a Geth hub is compared by Legion to the destruction of a city full of Geth.
 * Most "mobile platforms" contain a few dozen Geth and have intelligence limited to their designated task, though they can become more intelligent if additional platforms are nearby with which to network. The platform known as Legion is designed to operate outside Geth space and so contains over a thousand programs, enough for autonomous operation and dialog with organic sapients.
 * The Reapers are revealed to be this as well, by the end of Mass Effect 2. Legion points out this was already implied in the first game by comments regarding the nature of the first Reaper encountered.

"Alex: They're in me. They are me."
 * Considering the revelations in the climax of the second game.
 * Archons and Dark Archons from Starcraft is the result of the merge of 2 High Templars or Dark Templars (or later on, the combination). Ulrezaj is an extreme case, the merge of 7 Dark Templars. Also in Dark Templar Saga novels, Jake ana Zamara.
 * Ermac from the Mortal Kombat series was a single being created via the combination of a legion of souls by Shao Khan and tends to speak as "we" to represent this fact.
 * Kingdom Hearts: Sora.
 * As of Birth By Sleep, this turns out to also be true of . He's got in his heart.
 * Alex Mercer of Prototype. How he came to be like this is really, really tragic and frightening..


 * The Many in System Shock 2. In contrast to self-centered megalomaniac Shodan, who speaks in the voice of the legion, The Many alternate between separate and distinct voices. Humans assimilated by it begin slipping into the voice, though.
 * The Beast in Homeworld: Cataclysm is both. It converts spaceships and control them with it conciousness, but at the same time absorbs all the data it founds and uses it to form its speech pattern.
 * In Tales of Symphonia  proclaims she is this, although it seems  . It's unclear whether the souls comprising her will merge over time or not.
 * In Portal 2, it is revealed that rogue AI was constructed with at least one if not more uploaded human personalities in addition to the multiple contradictory directives and Restraining Bolts that Aperture Science tried to install to keep it in check.

Web Comics

 * Garth from Comedity, even most of the head-Garth represent part of his thinking process, the Muse and the Penguin is still quite independent.
 * Kano of Kagerou has this trope in addition to split personalities. A large part of the mystery of his character is trying to keep track of who he is at any given moment and figuring out whether a character in his head is actually a different person trapped there (like Red) or another persona of his (possibly Kid and/or Dark).
 * Homestuck has Tavrisprite, a fusion of Tavros, Vriska, and Jane's Sprite guide. The moment the fusion occurs, it screams in agony about how their personalities are irreconcilable.

Web Original

 * In Orion's Arm this the proposed explanation for how the minds of transapients work.
 * Also believed to be how sapient minds work, except that only one "node" can operate at a time as opposed to several in even the simplest transapient.
 * In addition there is polysophonce which operates more like Split Personality disorder.
 * There was also an individual that was thought to be an example of this, composed of thousands of sophonts, usually experts at something. Then it was revealed that: 1. The meta-sophont was really composed of the relevant sections and memories of the original sophont, and 2. the sophonts involved were all kidnapped over a long period of time, although the perpetrator is still at large.
 * Red vs. Blue has an unusual example. The Meta has a collection of A.I.'s in his head and continues to collect more. Since the A.I.'s are all fragments of an original A.I. it's a little unclear of how much individual personalities they - or their human host - retain.

Fan Fiction

 * Similarly to Dune, Points of Familiarity has a post-Third-Impact Shinji Ikari and the "Well of Souls." Near as anyone can determine, he is the last surviving human with a body. Everyone else lives in his head.

Theater

 * Depending on how you interpret it, the finale of Little Shop of Horrors might imply that Audrey II's victims have become this.

Western Animation

 * Coldstone from Gargoyles was created through cybernetics and sorcery from the remains of three separate gargoyles, and houses the minds of all three.
 * Happened once, temporarily, in Buzz Lightyear of Star Command. Buzz and Mira were fused together into a nasty blob-thing with eyestalks and two tongues, and their "internal arguements" formed much of the dialogue in the episode.
 * from Battle Force 5 has

Real Life

 * There is a theory that human minds work like this.
 * As well as Eric Berne's early model that essentially viewed some behaviour patterns as internal roleplaying sessions between one's learned roles (mostly reduced to basic "parent" and "child") and the part that isn't in this game and as such is more "rational". Which may be weird, but much less so than the facts he tried to explain.
 * In addition Friedrich Nietzsche once described the human mind as a bunch of conflicting souls (not the supernatural kind of course), with one soul in dominance.
 * Real Life people with Multiple Personalities generally describe their experiences as being more along the lines of this trope than that one.