Bond Creatures

""Ares the flier, I bond to you, Your life and mine are one, we two, In dark, in flame, in war, in strife, I save you as I save my life.""

- The Underland Chronicles

Bond Creatures choose a human partner to share their power. Often they can reject an unsuitable human partner or reveal a new ability or level of power if its Link and/or Synchronization with its human user is particularly high. In such cases they may form a Mental Fusion or allow the human to see through their eyes. They sometimes double as a Morality Pet.

A magic user's Familiar may (depending on specific interpretation) be one of these, as may a Sapient Steed, especially in case of Dragon Riders. Compare Empathy Pet, Empathic Weapon, Living Weapon, Attack Animal (possibly Equippable Ally) and Mons. In some cases an Imaginary Friend can also function as a creature or person bonded to the character imagining them.

See also Psychic Link for similar bonds between humanoids.

They definitely are not frickin sharks with Frickin' Laser Beams on their frickin heads... those are James Bond Creatures. Also not to be confused with Bond Girls, which are a different order of creature entirely. Compare Willing Channeler.

Anime and Manga

 * Bleach: In the anime series there is a race called Bounts, a vampire variant, each of whom has a Doll, which seems to be a type of elemental familiar. Dolls will turn on and kill a weak master; this suggests that although the individual Bount's elemental affinity is an internal characteristic that determines what Doll they can summon, the Dolls come from the environment and return to the environment when their masters die. Dolls don't take mates or reproduce.
 * Neon Genesis Evangelion sets the mold for spiritual/biological mecha series. While not sentient or even as independent as an animal, mechas in this series are picky about their human partners and may go crazy or refuse to work for the wrong pilot, or even the right pilot in the wrong state of mind. It is mentioned that human minds were either used as a pattern for the Evangelions' AI or were 'eaten' and partially incorporated by the Evangelions in development, and their taste in pilots is an effect of this. This series also shows a strong correspondence between the mecha's body and the pilot's body, with pilots feeling intense pain if the mecha is significantly damaged, for example by ripping off an arm.
 * The pain experienced by the pilot when the EVA is damaged is because they are neurally linked. That is, their nervous system are linked, which is what allows them to move so smoothly instead of in mechanical jerks.
 * Basically, the pilot thinks 'walk' (though on a more instinctual level), and the EVA does so. This is also why the EVA's are so picky with their pilots. There is in fact a certain bond required (The Marduk Institute keeps track of all these pilot prospects, not searching for them as is first stated) between pilot and EVA, and even with that bond, the EVA will respond negatively when the pilot is emotionally unstable. Which makes it bloody amazing that any of them can pilot them at all really...
 * Crosses into Nightmare Fuel territory when you realize that the pilots merge their souls and minds with the EVA to make it function.
 * In Gasaraki, the demonic looking Kugai, on which the Tactical Armours are based upon, require a certain individual known as a "Kai" to operate them, but first they must also be awakened by a unique ritualistic dance before the Kai can get the Kugai to "open up" so to speak...the Kai also acts as a 'sacrifice' of sorts, being a host that sits inside the Kugai, allowing it to move on its own, but the Kugai is still influenced by the Kai in terms of decision making.
 * In Idolmaster: Xenoglossia, mechas are powered by alien entities which seem to be telekinetic and of animal intelligence, but probably not human intelligence since they make no attempts at communication. Some mechas bond with a particular partner and will only work for them, while others aren't as picky.
 * In Dragon Drive, analyzing a teenager's genetic code reveals the dragon they are destined to partner with. These dragons cannot speak and usually go back into storage form when not being used for combat or transport. These dragons thus seem to be a manifestation of their owner's anima or subconscious, not independent creatures. One notable difference between dragons and owners is that dragons usually want to fight when their humans are afraid of overwhelming odds.
 * Digimon, depending on the season, choose their partners or have partners assigned to them by higher, godlike Digimon. The bonded Mons could "evolve" ("Digivolve" in the dub, to avoid confusion with Pokémon) when their partner was in danger or another condition was met. Sometimes a partner could inadvertently activate a Super-Powered Evil Side when attempting a forced evolution. In the first series, Digimon Adventure, if the partner lost their drive, the Digimon partner could possibly even devolve into an earlier stage.
 * Digimon Tamers upped the ante by, at least twice, having the human partners physically affected when their Digimon partners are injured in battle.
 * Duel Monsters in Yu-Gi-Oh! GX, particulary Judai and Winged Kuriboh, as well as Johan and the Gem Beasts.
 * The dragons in Dragonaut: The Resonance. Said resonance is what bonds them with their pilots, though some of the major dragon characters don't play by the normal binding rules.
 * Ayakashi and Mushi-Uta both have creatures that grant their partner great power, but with the cost that they will eventually either die or suffer some other horrible consequence.
 * The dragonets in Narutaru. They also count as a Deconstruction of the trope because the psychic link transfers everything the other feels -- especially pain.
 * In My-HiME, each Hime's child bonds to them through their love/affection for their most important person, bringing a variety of useful (and some not so useful) abilities. It is revealed early on in the series, that the Hime have to "risk what is most important to them" in order to use their child's power.
 * In Mai-Otome the Otome bond to those they protect and serve. It takes their master's approval to materialize their robes, but as the Otome take damage, the master also feels the pain, and if the Otome dies, the master follows suit.
 * The Rune Gods of Magic Knight Rayearth will test their charges to assess the strength of their will. If proven worthy, the Knight will get to summon and wear the Rune God's gigantic armored form into battle, and the Rune God's strength and abilities grow directly in proportion with the Knight's fortitude. The downside is, any injuries the Rune God sustains, the Knight will get too. This is much more notable in the Alternate Continuity of the OAV.
 * Caro and Lutecia of Magical Girl Lyrical Nanoha possess some sort of link with their summoned creatures. This was best seen during their final battle, where on Lutecia caused her monsters to cry Tears of Blood and the less intelligent ones to go berserk.
 * The Mamono/Mamodo from Zatch Bell need to find a human partner to supply Heart Power and activate spells while taking part in the king-election tournament on Earth. While a few of these pairs develop Psychic Links, the Heart Power-link is actually due to the rules of the tournament rather than part of the Mamono's nature and the Mamono don't even get to choose their partner themselves.
 * The Mulian mecha in RahXephon function like this, bonding with individuals called "Instrumentalists". It responds to its pilot's moods, and will act autonomously to protect its pilot if the pilot is in distress.
 * In Naruto, Samehada is a "frickin shark" bond sword. The sword chooses its wielder based on their amount of energy and the taste of it, though it can be forced to be loyal to a previous wielder if that wielder has enough power or a strong relationship with it. If an unfit wielder tries to use it, spikes protrude from its handle and it runs back to its true master.
 * In Yu Yu Hakusho, Yusuke received an egg that would hatch a spirit beast. If he's good it will be this. If he isn't, the beast will eat his soul. The egg he originally got would have been the latter but he sacrificed it to save Keiko. He gets another and it ends up hatching a good spirit beast, Puu.
 * Soul Eaterhas Demon Weapons. They seem to be a werewolf variant, created by experiments a witch carried out on humans in the distant past, but transforming into a weapon instead of an animal; they are born and age like humans, are capable of reproducing with humans and having human children. They are thus unique among anime examples of bond creatures, following more of a western model. The bond is also not lifelong, and can be friendly or romantic.
 * Soul Eaterhas Demon Weapons. They seem to be a werewolf variant, created by experiments a witch carried out on humans in the distant past, but transforming into a weapon instead of an animal; they are born and age like humans, are capable of reproducing with humans and having human children. They are thus unique among anime examples of bond creatures, following more of a western model. The bond is also not lifelong, and can be friendly or romantic.

Comic Books

 * Elf Quest by Wendi and Richard Pini features a tribe of 'native american elves' which bond with wolves as mounts that they ride mainly while hunting. Unlike many types of creature bond, this does not take place at birth, one partner can survive the death of the other, and an elf whose wolf has died can bond with another one.
 * Considering that the elves' lifespans are substantially longer than normal wolves (Pini elves can live thousands of years IIRC), they rather have to be able to survive the death of the other.
 * In one of the stories from the Elfquest anthology novel The Blood of Ten Chiefs it is explained the Wolfrider wolves are, in fact,  All Wolfriders are descended from   So while the Wolfriders are   the wolves they ride are   This allows Wolfriders and their wolves to form strong telepathic bonds similar to the bonds elves form with their 'soul-mates.'
 * The Venom symbiote from Spider-Man fits about every aspect here. It grants power to its hosts, more the more closely it binds - why Venom is stronger than black-suit Spiderman. It is also capable of abandoning its hosts- leaving a particularly inept one mid-jump to plummet to his death.
 * This may vary from host to host, though. While it "shares" power (feeding off of the host's adrenaline), it can also take over (Peter Parker's sleep-slinging as an example).
 * The Ghost Rider is a mortal man bonded with a demonic entity; the original, and largely most well known Rider is motorcycle stunt rider Johnny Blaze and the demon Zarathos.
 * Writer Jason Aaron's run retcons this; the Spirits of Vengeance are living spirit-weapons from Heaven (albeit not angels), bonded to mortal hosts.
 * Green Lantern rings (Actually, all of the spectrum rings for that matter) seek out hosts that they deem worthy based on their personal settings. Green Lanterns are chosen for their willpower, Red Lanterns for their rage, Yellow Lanterns for their ability to cause fear, etc.

Film

 * In Avatar, the Na'vi create mindlinks with various animals, most notably the "banshees", which are similar to dragons.

Literature
""Shut up Loiosh.""
 * Timothy Zahn's Dragonback books feature the K'da, a dragonlike sentient race with the capability to become a two-dimensional 'tattoo' on the skin of a host/symbiote, with the corollary that if they go for more that six hours without doing so, they turn 2D anyway and die. Normally their hosts are a race called the Shontine, but when the K'da warrior Draycos bonds with the human Jack Morgan, he becomes healthier, stronger and smarter, and even gains new powers--.
 * The night horses in C. J. Cherryh's Rider series are a horse-shaped carnivorous telepathic alien species. The horses bond with humans since they enjoy the complexity of the human mind, and ham, and humans bond with the horses so they'll help protect the humans from the world's other telepathic carnivores, which like to pull Jedi Mind Tricks in order to eat the humans.
 * David B. Coe's The Lon Tobyn Chronicle has an entire order of people who form bonds with otherwise ordinary animals, mostly birds. The birds don't stay with the humans forever though, they die just as ordinary animals would.
 * Alan Dean Foster's Humanx Commonwealth books portray an empathic bond between Flinx and the minidrag Pip. She amplifies his Psychic Powers whenever she's in his proximity.
 * Midworld showcases a unique plant/human symbiosis in the form of the furcots, intelligent guardians created by the to act as lifelong companions for the humans living there.
 * Gayle Greeno's Ghatti's Tale series is a modern Fantasy series in which the telepathic animals are Ghatti,large catlike animals that can only speek mind to mind.
 * Peter Hamilton's The Night's Dawn Trilogy trilogy: biotech can be used to create bond creatures. Those that matter most are Voidhawks, sentient living starships which bond with a captain, conceived and gestated at the same time the voidhawk egg is laid. There are also Blackhawks, a voidhawk variant, with a shorter life span but greatly improved combat performance which are used by 'independent' captains, who purchase the eggs and bond as adult via an implant.
 * It is also shown that humans can be "bonded" to other humans, leaving them at the mercy of their master. They can then be observed, controlled or killed at will.
 * Robin Hobb's Farseer trilogy has the Wit (aka The Old Blood) which allows certain bloodlines to bond with animals. Not all animals are candidates for bonding, only those also of the Old Blood. The protagonist's bond is with a wolf called Nighteyes. The bonding process can go horribly wrong, as the protagonist learns more about when he is able to spend time in a Witted community. (They are discriminated against, and must hide their relationships with their Bond Creatures in all but their own closed communities.)
 * He encounters a man who as a baby bonded with a flock of sparrows. The man effectively has no mind of his own, as his mind was linked so young to a lot of small, not very bright creatures scattered all over the place.
 * The protagonist himself is considered to have bonded too young, and to have interfered with Nighteyes' development as a wolf; those who were brought up in Witted culture are expected to let their Bond Creatures live 'naturally' and without interference. (The fact that Nighteyes doesn't want to dig his own lair and actually prefers living in the protagonist's quarters doesn't help them defend themselves from disapproval.)
 * The animal partner in the bond can allow the human partner to survive in the animal partner's mind after the human's death. The Witted community considers this a violation of the animal partner's right to live his or her own life (since the human's instincts are expected to be at war with the animal's).
 * In P.C. Hodgell's Chronicles of the Kencyrath series, the ability to form a psychic bond with an animal is one of the more common of the Shanir abilities, common enough that about a dozen students in Jame's year in the Military Academy of Tentir have it in various forms. Jame becomes bound early on to an ounce, a medium-sized hunting cat; blind from birth, the cat learns to see through her eyes across the link, and occasionally shares its senses with Jame.
 * Mercedes Lackey has multiple types of Bond Creatures in her Heralds of Valdemar and related books.
 * Companions resemble pure white Cool Horses, and function as combat mounts and a badge of being a Herald of the nation of Valdemar. They are sentient and have an independent existence including reproducing themselves. In a later book it is revealed that Companions are, in fact, mostly reincarnations of former human Heralds (a rare few are so-called "Groveborn", who could be seen as incarnated minor angels). Strictly speaking, the Companions are not natural creatures; the first few were incarnated by an unnamed deity as the answer to a heartfelt plea made by the first King of Valdemar for some way to guarantee the continuing good and just governance of his new nation.
 * Later in the series, we meet the Firecats—huge feline reincarnations of the high priests of Vkandis (the ones he approved of, not the ones who got the entry over at Corrupt Church).
 * Bondbirds are large birds of prey that are basically animals, although they may be a bit more intelligent than earthly ones. Bondbirds demonstrate Animal Think, commenting on their humans' lives in terms of nests, mates, hatchlings, prey, and other bird-isms. They were specifically bred for their roles by the Tayledras mages who live in the magic-damaged lands surrounding the Dhorisha plains.
 * This is also how dragon mages work in hers and James Mallory's The Obsidian Trilogy: one dragon and one human or elf are, on some deep level, compatible as platonic soul mates, and they can bond with each other, the mage learning to channel the dragon's vast power through their body. Unlike most forms of magic in the Obsidian Trilogy, requiring require payments and debts, dragon magic has no such requirement—because the dragon's life is inextricably linked to its partner's, and while dragons live nearly forever, even elves do not. The sacrifice this represents means that all magedebts are paid, forever, no questions asked. Dragon mages are, understandably, both feared and desired by both the allied races and the Endarkened.
 * The bonds between elves and unicorns are similar.
 * In Lackey's "Skitty" stories—a loose sci-fi adaptation of the Dick Whittington myth—ships' cats are genetically-engineered high-intelligence creatures, some of whom—like the title cat—are telepathic with their handlers.
 * Anne McCaffrey is probably the archetypal example of bond creatures. Her Dragonriders of Pern series features dragons with near-human intelligence which choose a human partner at birth (this is called Impression) and two rarely outlive each other (and certainly don't want to). Fire lizards has a mild variant of the Impression (normally it merely helps to organize their swarms, but was turned Up to Eleven for dragons). Less well known but also interesting, this author's The Ship Who...... series features spaceships powered by the human minds of people whose bodies were defective or injured, and these Sapient Ships, also known as Brains, form partnerships with human Brawns. This bond is not permanent, it may be friendly or romantic, and the telepathic element is enabled by technology.
 * Early in the series, it's indicated that romantic feelings between a Brain and his/her Brawn is grounds for the partnership being broken up, as a Brawn who becomes too attracted to his/her Brain partner may become obsessed and attempt to access what is left of their body, which will kill the Brain. They find a way around this later, using androids.
 * McCaffrey's dragonriders are parodied in Terry Pratchett's The Colour of Magic, where the dragons only exist because their riders believe in them. Similarly, the dragon in Guards! Guards! is bonded to, much to his discomfort.
 * More recent Pern books, particularly those which Todd McCaffrey worked on, establish that whers—dragons' humbler, uglier cousins—also form psychic bonds with humans. Unlike either dragons or fire lizards, whers can sever their bond voluntarily if they form a solid emotional attachment to a different human, and the death of one partner needn't provoke suicide by the other (though it can) when a wher is involved.
 * Sarah Monette and Elizabeth Bear did a brilliant and weirdly hilarious Darker and Edgier spin on some of the less charming implications of the Pern series in A Companion to Wolves, which is pretty much Pern WITH VIKINGS and giant sentient wolves replacing dragons.
 * Andre Norton created several of the oldest examples of Bond Creatures in western fiction: The Beast Master, Falconers in the Witch World series and more. Probably she was the inspiration for Mercedes Lackey's and Anne McCaffrey's later evolutions of the concept.
 * Robin D. Owens is a current science-fantasy romance author whose Heart series features telepathic cats called Fams (short for Familiars like witches' familiars) which bond to human owners.
 * Similar to the Pern examples (some would say too similar) are the dragons and riders in Christopher Paolini's Inheritance Cycle. Dragons and riders form a mental bond, can share each others energy. Dragons can't rarely survive the rider's death but riders can usually survive the dragon's death at the cost of their mind.
 * Jennifer Roberson's Cheysuli series shows a semi-intelligent empathic alien species of which individuals occasionally (but not usually) bond with humans. (Although the series this troper read showed individuals of various animal species blessed by the gods with high intelligence with the specific intention of bonding with humans...)
 * David Weber's Honor Harrington series has treecats, cute, furry, seriously lethal aliens with empathic abilities; mostly they maintain their own society, but on rare occasions one will form a lifelong psychic/emotional bond with a human, such as our heroine Honor.
 * It's described as looking for a glow that fits right with their own. The bond is for life, but while on a planet a 'cat will feel free to go out and seek companionship with its own kind from time to time. 'Cats used to consider this a bonding a bittersweet condition because when the human dies, so does their own will to live. The existence of prolong means humans will eventually learn the pain of the other way around. The other hook is that with exposure to humans, the Treecats have learned sign language and are now able to talk rather than just communicate empathically and non-verbally with their bond humans.
 * The Temeraire universe subverts the magical psychic soulbond stereotype, in that the bond between dragons and handlers is entirely emotional, rather like a platonic marriage - and like a marriage, they can go horribly wrong, with neglect, abuse, abandonment and heartbreak all inferred over the course of the novels. Still, for the most part dragons and their captains share an intense and mutually beneficial relationship that ends only with the death of either or both of them. The bond is such that British captains (and probably captains of other nations too) rarely marry, as they couldn't share themselves between a dragon and a spouse; when they want sex (or heirs) they have scandalously casual relationships with other aviators, treating it as matter-of-factly as the dragons do.
 * Two races from the Codex Alera have this as a power- the Marat (basically, to elves what neanderthals are to humans) can form a permanent empathic link with another living thing that lets them share in some of its abilities, while the titular Alerans bond with the elemental spirits called furies, allowing them to share in the furies' magic.
 * She wanted a horse.
 * Yeah she did.
 * The Vlad Taltos novels play with this trope with Loiosh and Vlad, to the point of being a Take That at the Pern novels' fire-lizards.

"When a Tusken Raider child reached the age of seven he or she was ceremonially presented with a bantha of the same age as a companion for life. The youth learned to care for the creature, and the two built a mystical bond between Tusken and creature. When the bantha reached maturity, the male Tusken Raider would saddle his companion and ride it into the desert for adult initiation ceremonies. When Tuskens married, the couple's banthas would also mate, and when the Tusken pair had a son or daughter, their banthas tended to have a calf of the same sex. The banthas of Tatooine were known to form deep bonds with the Tusken Raiders of the planet and often committed suicide if their riders were to die first. Banthas which died naturally were placed in vast graveyards, which held a kind of ceremonial reverence with the banthas."
 * In the Star Wars Expanded Universe, banthas (the big woolly, horned beasts of burden in Episode IV) were paired with young Tusken Raiders as companions for life. From the Star Wars wiki:


 * The daemons in Pullman's His Dark Materials trilogy are a variant of this - bonded to their human because they are the physical embodiment of that person's soul, and in the case of children, will change into different animals depending on their partner's emotional state. Interesting in that the daemon's gender is always the opposite of the human's.
 * Not always true, since early in the first book Pullman mentioned a male character who had a male daemon. Even so, these are pretty rare.
 * In The Underland Chronicles, bats and humans can bond and vow to make the other's safety their first priority.
 * In Robert Heinlein's Starship Troopers, the human handlers of the Federation's K-9 units form this type of relationship with their Neodogs (basically, modified dogs with near-human intelligence). One of the recruiters Rico meets (a former K-9 handler) tells him that the bond between Neodog and handler has been said to be more intimate than many marriages. If a handler dies, SOP dictates that the Neodog is put out of its misery. If a Neodog dies, the handler is given lots of therapy, but is generally psychologically scarred for life.
 * Princess of Wands: The cat revived in the last story of the book becomes this after it's revived by the protagonist, to the point of the husband commenting that the cat's acting like Barbara is creeping him out.
 * The Seventh Tower has Shadowguards and Spiritshadows, which the Chosen bind to their wills.
 * A Song of Ice and Fire has the Stark children and their direwolves sharing a unique bond. To an extent other wargs found throughout the story share this with their chosen animal thralls. However, the direwolves and their owners appear to share a deeper connection as Jon notes that Ghost isn't merely a thrall, but actually a part of him.
 * Dinotopia has this, most notably with Skybax riders. Only the rider can approach a Skybax, and the bond is a lifelong one once established. The novice rider must prove himself or herself to the Skybax to be considered for full apprenticeship. This often involves a climb up into the Forbbiden Mountains to the Tentpole of the Sky, a way of showing that the rider is not bound to the earth. The loss of a rider can send a Skybax into a state of feral aggression as with Windchaser. It can happen with humans and other species if they're born/hatched and raised together sometimes; this is known as 'nestfriends'.
 * The novel The Wild Boy features a future where bear-like aliens have taken humans as a replacement for their bond-creatures, who went extinct. The Lindauzi call humans dogs, and raise them in kennels. The packs of free humans are wolves. Most often, a young Lindauza is given a human bond mate on his or her upright day, the first time he or she walks on two legs. If human and Lindauza are seperated, the Lindauza becomes ill and can die. There's something of an ability for each to sense the other when they're near.
 * The novel Pegasus has this as the result of a spell performed to bind a human to a pegasus, which happens as a young person's right of passage. Most share a type of simple telepathic communication, but only the protagonist's pegasus speaks in actual language.
 * In the Cordwainer Smith story "The Game of Rat and Dragon" humans bod with cats to fight Eldritch Abominations living in hyperspace.

Live Action TV

 * The Trill from Star Trek are a symbiotic race that live inside a humanoid host. The symbiote lives for centuries, but the host is subject to the same frailties as a normal human. In Star Trek: Deep Space Nine, Ben Sisko was an old friend of the Trill Dax, who had recently taken a new female host named Jadzia. The joke was Sisko had known Dax for years as old man named Curzon. Later on in the series Terry Farrell left the show, and the Dax symbiote passed on to a new female (of course) host.
 * The Goa'uld of Stargate SG-1 live inside humanoid hosts. They are more parasitic than symbiotic, except for the Tokra who only accept willing hosts and only take control when necessary.
 * The Riders in Kamen Rider Ryuki (and by extension Dragon Knight) gain their powers by forming a bond with a Mirror Monster, turning it into a Contract Monster and providing them with cards of power they use in combat. Contract Monsters have their own personalities and tend not to like Riders whose personality clashes with theirs or who avoid battle (since they eat the essence of Mirror Monsters to survive). A particularly extreme example is Kamen Rider Ohja, who kills two Riders and forces contracts with their Monsters when they attack him seeking revenge. They openly despise the man and attack him when the opportunity comes up, but because of the contract they're forced to work for him.
 * While this is supposed to be the case when one bonds with an Ultraman, it is only in Ultraman Nexus where it is actually played out in great detail. Second dunamist Jun Himeya, for instance, often has to deal with the the injuries that he suffers when in Ultraman form whenever he reverts back to his human form. Conversely, there were episodes where Nexus can't fight effectively because of the injuries that Himeya suffered while in human form.
 * And then there is the metafield that Nexus generates in order to fight monsters in, which is revealed to be  And you realize that   Fridge Horror indeed.
 * It is heavily implied in Doctor Who that TARDISes are bonded to their Time-Lords. The Doctor and the one he stole certainly have a psychic link, to the extent that her translation circuits will stop if he's unconscious. The reaction seems to put them very much on equal footing, as the episode "The Doctor's Wife" implies, with the TARDIS
 * The makri, a spider-like creature in the season two finale of Sanctuary lives symbiotically with its chosen host, also establishing a telepathic link to another abnormal. Once it leaves the host's body, the host dies. Will proves to be a particularly good host as he doesn't die when the Makri leaves and he is still able to communicate with Kali, the other abnormal the Makri is connected with.

Tabletop Games

 * GURPS has an entire mechanic devoted to these kind of characters (Allies with the summon-able enhancement).
 * Dungeons & Dragons has a quite a few ways of making these:
 * The Kalashtar from Eberron are a race of humans descended from a group of humans who bonded with psychic entities called Quori. As the original bond members had children, the single Quori spirit was split along the lines of all descendants of the same sex.
 * Beastmaster Rangers in Dungeons & Dragons 4th Edition are defined by their bond with a particular beast that fights alongside them. They even gain a special ritual to bring it back from the dead.
 * Similarly, the Shaman class has a bonded spirit companion, which acts as the nexus for a number of their ally-boosting abilities.
 * A Blue Rose character can have a rhydan (a sentient wolf, cat, horse or dolphin) as a Bond Creature by taking the Rhy-Bonded Feat. Since the rhydan species are themselves playable races, you can also play a rhydan character who has the Rhy-Bonded Feat and a human Bond Creature.
 * The Summoner base class in Pathfinder has the ability to summon and form a bond with a special outsider known as an eidolon, which gains power as the summoner gains levels and forms a bond with the summoner, and the two become linked over time, eventually even sharing a shard of the same soul.
 * Warhammer 40,000's Gyrinx is another pseudo-cat creature, whose temperament tends to match the owners. An obscure creature both in-setting and in published works, they tend to be drawn to psykers, and are particularly associated the the Eldar.
 * Also present are the various creations and creatures serving as familiars to psykers. These range from the weird (genecrafted two-headed cyborg eagles) to the macabre (Servo-Skulls, the skulls of loyal Imperial servants used after death to house a small anti-grav drive and various arcane technologies) and the downright disturbing (vat-grown mind-wiped babies with implanted anti-grav units and decorative wings serving as Cherubs). And that's before the servants of Chaos are even considered.
 * Huron Blackheart, the Tyrant of Badab and leader of the traitorous astral claw has his 'Hamadrya' which is an unknown creature that is bonded to him and grants him mental powers.

Video Games

 * The main characters of Drakengard have entered a Pact with another creature; ranging from a Golem to a Dragon.
 * The Aeons of Final Fantasy X demand that the Summoner enter an intense, soul-binding pact with them before yielding their power. Extends to the gameplay, as Yuna's Aeons grow in strength depending on her own stats..
 * Guardian Forces in Final Fantasy VIII are explicitly "junctioned" onto the caster's mind, literally taking up space and even degrading the person's memories if junctioned for too long. On the other hand, they provide the ability to draw and cast para-magic.
 * It should be noted that only the Aeons and Guardian Forces require this. The Espers, the Summoned Monsters, Eidolons and Red Materia will obey anyone who summons them; a few of the more powerful ones will battle the candidates to test their mettle, but there is no soul or mind-bonding involved. In Final Fantasy IV, however, Summoners whose Eidolons are killed, die as well.
 * This is a (if not THE) major ability of multiple classes in World of Warcraft. Warlocks get demon familiars by defeating them at the end of various quest chains; Hunters can tame wild animals; in both cases the pet levels with or slightly behind the character, gaining occasional new abilities. Both have a talent specialisation that focuses on this aspect, empowering both the master and the pet. Hunters have a somewhat more involved relation with their pets, having to care for their happiness (most commonly through feeding, with different animals liking different food), health and even a talent tree for the pet itself (though there are only 3 possible trees and the specific type of animal only determines one ability), while Warlocks can't even name their minions (the name is derived from the warlocks own name) and force them into doing their work, as evident by several of the demons responses, most notably the familiar and the felguard.
 * Deathknights and Mages can also have permanent minions under certain conditions (ghoul and water elemental), but they don't have the same connection nor a consistent entity to serve them (ghouls get named randomly but change every time you summon a new one. Elementals get no name at all).
 * In Dwarf Fortress, cats have a tendency to behave like this... the downside is, they don't fight; apart from killing vermin, they're just Small Annoying Creatures.
 * Lost Souls MUD has a number of guilds built around an empathic bonding faculty vaguely inspired by His Dark Materials.
 * FM beings in Mega Man Star Force. The fusion is two way in that both parties can attempt to assume control. The main character's partner usually gives him control except for certain cooperative moves, hosts of villanous aliens either get consumed or try to fight for control (which apparently forms a composite mind), and one villain (in the anime) actually only controlled her host while the latter was asleep to sidestep the issue.
 * Ra-Seru in Legend of Legaia are symbiotic creatures that are immune to the effects of a mist that turns normal Seru (and usually their hosts) into mindless monsters. Seru can exist separately from a host, but their attachment grants powers and magic far beyond the normal.
 * Pastamancers in Kingdom of Loathing can form a bond with certain creatures, provided they have the correct item. Only one bond can be held at a time, though, and forming a new one severs the link to the old one forever.
 * In Pokémon Ranger, a Mon bonds with your character, lending you strength and help during a battle.
 * In The Legend of Zelda Skyward Sword, the Skyloftians have their personal Loftwings, Giant Flyers which come at their call and serve as transportation across the sky.

Western Animation

 * The Avatar in Avatar: The Last Airbender is implied to usually have some sort of creature that is called their animal guide. Aang has Appa and Roku had a dragon, both of which appear to be of about human level intelligence. Airbenders also traditionally bond with a sky bison when both are young and it is stated that it is a lifelong bond.
 * Korra in the sequel series, The Last Airbender: Legend of Korra, has a Polar Bear/Dog hybrid called Naga.

Other

 * Limyaael calls these types of creatures telcoms, for telepathic companion.

Real Life

 * Among the Luiseno Indians of Southern California, part of a boy's initiation consisted of having visions of a particular animal (for example, a rattlesnake, bear, or deer). It was believed that the boy and the vision animal became bonded as friends or allies. After such visions, the boy would always treat his vision animal with great respect and it is believed that his animal could communicate with him and serve as his adviser.