Heroic Host

Eat your heart out, John Carpenter.

Heroes perform amazing feats, save the day and everything's golden. But Where Do They Get All Those Wonderful Abilities? The answer is an alien (or demon or robot) latched on and the hero gets some nifty superpowers as a result. Often times this tenant will be a Superpowered Alter Ego and may not share the hero's agenda.

Different types seen include: Vermiform invertebrates, Parasite Zombie, vampirism, Adaptive Armor, Artificial Limbs, Clingy Costumes, bystanders, and villains.

This is when a Viral Transformation works smarter and You're Nothing Without Your Phlebotinum can actually be true; for the more holistic transformation see Fusion Dance. Compare with The Symbiote as it is a similar "other being causes Super-Empowering" trope. Also compare Powers via Possession, Willing Channeler, Pro-Human Transhuman, and Bad Powers, Good People; contrast Superhuman Transfusion, Symbiotic Possession, Transhuman Treachery, and Bad Powers, Bad People.

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Examples:

Anime & Manga

• In Bleach, Ichigo's Hollow powers are the result of the remnants of Aizen's experimental Hollow White that had infected his mother Masaki being passed on to him at birth. These remnants merged with Ichigo's natural Shinigami powers which he inherited from his father and became his Zanpakuto Zangetsu.
• Akira Fudo from DEVILMAN crybaby is currently the vessel of Amon, who is one of the — if not the most powerful demon out there. However, he's able to retain his humanity throughout and fights to defend humans, unlike Miko (whose personality worsened, even if it was temporary and never really got too far) and Moyuru (who eventually defected to the demons' side).
• D.Gray-Man, parasite type Innocences are physically integrated into their wielder and so can exert some control over their personalities, but give the hosts incredible powers as a result. The primary user of such an Innocence is a mock-vampire due to his Innocence, which manifest as shapeshifting fangs that allow him to grow stronger by consuming the blood of enemy mooks.
• Hell Teacher Nube, although closer to Sealed Inside a Person-Shaped Can then usual. Although he's extremely skilled and powerful even without the help of his Oni Hand, many of the critters he encounters would be unbeatable or at least extremely difficult to approach without it.
• The Aburame clan of Naruto act as human hives for armies of destructive bugs, who live off their chakra and can swarm and poison enemies.
• Parasyte has the titular shapeshifting parasites that burrow into a human host's head, eat their brain, and take over the body, resulting in intelligent but emotionless monsters that look human and kill regular humans for sustenance. When the parasites screw up the takeover and end up replacing a different body part than the head, you'll end up with the parasite Sharing a Body with the human host. This is the case with the main character, whose arm is replaced by a parasite, and the two must learn to work together to fight the other parasites who consider this duo a threat.
• Project Arms, cyborg bits with artificial intelligences.

Comic Books

• Alpha Flight: Sasquatch originally thought he was that way due to gamma rays (a la Hulk) but it turned out he opened a doorway into another dimension, through which a Great Beast was able to come through and bond with him.
• Blue Beetle: The scarab is a semi-sapient piece of alien tech that is essentially weaponized Powered Armor: it bonds to a host and encases them in a supremely powerful suit of exo-armor... whilst simultaneously taking over their mind and turning them into a slave-warrior of the Reach, the scarab's creators. Fortunately for the Blue Beetle, his scarab was damaged before bonding with him, allowing him to retain control.
• Captain Universe: The Enigma Force is different in that it bonds with a different person each time, turning them into Captain Universe.
• Creature Tech: An alien parasite rips Dr. Ong's heart out, then attaches itself to his chest and serves as a replacement heart. It also provides him with several extra limbs, skills in hand-to-hand combat (the thing can learn kung-fu by watching movies), and when Ong gets really upset, teleportation powers.
• Darkhawk: Chris Powell is a young man who literally stumbled onto alien tech.
• Ghost Rider: The various Ghost Riders are humans possessed by Spirits of Vengeance, who use the powers of Hell to fight evil.
• Iron Man: War Machine had at one point Eidolon Warwear, which was basically living technology.
• Jonni Thunder: Jonni timeshares with the alien energy-being Mzzttexxal.
• Sleepwalker: Rick Sheridan serves as this for Sleepwalker, as Sleepwalker is trapped in his mind and can only come out when Rick's asleep.
• Spawn overlaps this with Clothes Make the Superman; a significant portion of his powers stems from K7-Leetha, the cloth-like demon bonded to his skin as a living costume.
• Spider-Man:
  • Spider-Man was this during his time with the symbiote, though for most of their time together, he didn't even realize it was in the passenger seat.
  • Venom tries to be this at times, depending on the host (Eddie Brock pulled off a decent Anti-Hero, Mac Gargan faked it, and Flash Thompson is this until the symbiote freaks out and starts eating things). Anti-Venom tries, but Eddie's a little too... off in the head by now to pull it off for extended periods.
  • Spider-Gwen becomes this after losing her original spider bite-induced powers. The only way she could get them back (and save her friend Harry Osborn in the process) came in helping to create and subsequently bonding with her universe's version of the Venom symbiote. While this did lead to a similar stretch to Peter where she had to deal with increased aggression, it eventually fades once the symbiote is exposed to more positive emotions, and the only "negative" she's had to deal with since is a greatly increased appetite as she now eats for both herself and a hive mind of "gummy spiders".
• Toxin: Patrick Mulligan due to having one of The Symbiotes bonded to him whilst trying to use it to do good.
• Top Cow Productions: The artifacts from the Top Cow Productions universe: The Witchblade, The Darkness, and The Angelus. The Darkness and Angelus are opposing ancient powers that inhabit human vessels, granting them powers, while their child, the Witchblade, is a sentient gauntlet that forms a symbiotic relationship with its host, also granting them powers.
• X-Men: One of the most famous examples is the Phoenix Force, when hosted by Jean Grey (mostly — aside from insanity induced by Mastermind), Rachel Summers (completely), the Phoenix Five (pre Sanity Slippage), Hope Summers (completely, but briefly), and Quentin Quire (for a decidedly given value of 'heroic').

Fan Works

• Downplayed in Amazing Fantasy. In the sidestory, "Let the Devil In", Bakugou already had powers before meeting Venom and is quite the Jerkass, but he ultimately uses his powers to fight for good, even if some of his motivations are less than heroic.
• Child of the Storm has Harry intermittently functioning as a willing host of the Phoenix Force. In the sequel, he discovers that he can actively use the fragment of the Phoenix inside him as more than just a Defense Mechanism Super Power. This is not necessarily a good thing. One round of Break the Cutie too many, however, leads to him snapping and becoming the Dark Phoenix.

Film

• Resident Evil: Apocalypse: The T-Virus gives Alice super abilities, which she uses to fight zombies.
• Severed Ties (1992): A desperate scientist injects himself with a reptile based regeneration serum to return his arm count to two, which worked out fairly well as long as one didn't mind the mouth, or teeth, or eyes ... and fed it.
• In Turning Red, the red panda spirits that possess the women of Mei's family enable them to turn into giant red pandas.
• In Upgrade, the STEM chip lets Grey walk again, and when he lets it take full control over his body, it turns him into a nearly unstoppable Action Hero with superior reflexes and full use of his Uninhibited Muscle Power. The thing is, STEM has a mind of its own. In fact, it engineered the accident that left Grey paralyzed in the first place, as it was seeking a healthy human host and saw him as a perfect candidate, and then manipulated him into pursuing revenge against the goons who he thought were responsible (which was actually STEM cleaning up loose ends).

Literature

• Dark Future: Krokodil becomes the Host of the Ancient Adversary, the Pawn of the Nullifiers. Exactly what the nature of the Ancient Adversary is is never made entirely clear during the series. However, it seems to take the form of a crocodile and is connected in some way to the Moon. It's certainly been around as long as Seth and the Dark Ones have and it's probably not good, just antithetically opposed to them. Being its host gives Jessamyn some degree of supernatural invulnerability and some extra super-strength on top of the cybernetic augmentations she already had.
• In Dis Acedia, most of Shroud's powers come from Shade/Manah, the manipulative spirit inhabiting his cloak.
• Eden Green and the sequel New Night portray humans unwillingly infected with an immortal needle parasite, most of whom choose to use its horrifying abilities to protect others.
• A short story titled Idiot's Crusade has an alien quietly fuse with the stupidest kid in town to study humans For Science!. A side effect of this is that the boy gets a massive amount of powers (and total control over them), but without any enhanced intelligence. This leads to a rather disturbing ending, where the boy, in an effort to make the world "happier", decides to go to the UN building to use his powers to improve the moods of the world leaders (while still lacking the mental capacity to think out the effects or ethics of his actions). Meanwhile, the alien realizes there is no way for him to detach from the human, meaning the idiot is guaranteed his powers for quite a while.
• The heroes of The Kane Chronicles serve as vessels of the Egyptian gods.
• A Mage's Power: After a trial in a desert, Eric is given the spirit of Dengel, a legendary mage. He has access to all of Dengel's knowledge which gives him a leg up on older mages. However, he does not have Dengel's spiritual might and so he has to make up the difference with guile.
• In Pact, after Blake Thorburn invites various local spirits in to fill the gaps in his being, they take the form of mobile bird tattoos on his arms. He can remove them to send them to do minor tasks for him, such as moving objects or powering Sympathetic Magic, but at significant cost to his own metaphysical stability.
• Pale: Brie Callie is the host to the Hungry Choir, a living ritual, which allows her to extrude portions of the Choir, in the form of starved, bloody-mouthed children who can either attack her enemies or shield her.
• Parasite Eve: For the most part, the Neo-Mitochondria (Mitochondria who have developed a Hive Mind sentience) are simply The Virus, but in a few people with just the right DNA (read: Aya Brea) it instead becomes a powerful, symbiotic force, granting Super-Strength, Hyperactive Metabolism, Pyrokinesis, and the ability to kill people on the cellular level with your MIND. And probably pick out winning lottery-tickets, too.
• Seen in Perry Rhodan once in a while. For a time, the eponymous protagonist himself had "Whisper", an intelligent alien symbiont who could be worn like a cloak and in exchange for regular baths in a protein-rich nutrient fluid endowed his wearer with telepathy and enhanced night vision; for another example, part of the entire culture of the Duchy of Krandhor was the common use of "spoodies", tiny insectoid creatures that implanted themselves under the host's skin (usually on top of their skull) and provided a measurable intelligence boost.
• Nearly all Surgebinders from The Stormlight Archive are this. They get powers from having spren bound to them by having a quality matching the quality that the spren stands for. Kaladin, for example, is an honorable person and thus is bound to an Honorspren. The powers increase as they choose to embody the ideas of their spren, with the spren eventually becoming an extremely powerful living weapon. If they reject that quality or idea, they kill the spren instead.

Live-Action TV

• Kamen Rider has a couple of examples:
  • Ryotaro Nogami, Kamen Rider Den-O, is (by his own admission) a Non-Action Guy; but as a Singularity Point he can still maintain control of his body even when possessed by Imagin. His good nature and Heroic Willpower are what brings the team together and creates both of Den-O's Super Modes, Climax Form (which requires the Imagin to work together as a team) and Liner Form (in which Ryotaro fights on his own without being possessed).
  • Haruto Souma, Kamen Rider Wizard, became a magic-user by resisting his Despair Event Horizon through Heroic Willpower (those who don't are killed and replaced by their own inner Phantoms). Since then, he's made it his mission in life to be the "final hope", preventing others from falling into despair and becoming Phantoms. When his Phantom was destroyed, he ended up bringing it back to life in order to protect his friends, and thus created his Super Mode Infinity Style. For its part, Haruto's Phantom gradually goes from Teeth-Clenched Teamwork (since if he dies, so does it) to actually respecting him and being a willing partner.
• Blending with a symbiote in Stargate SG-1 can result in this: the human (or other creature) gains greatly increased healing abilities, a near-perfect immune system, and an elongated lifespan. They also get the sum total of all the knowledge of the symbiote. The downside? They have to share their body and mind with another intelligent creature. The Tok'ra believe that equal sharing of the body between symbiote and host is the proper way to do this, and only take unwilling hosts in extreme circumstances. The Goa'uld do not share such morals.

Roleplay

• Temporarily in Communication, Homura and Madoka become possessed by their future selves in order to deal with the Alien Invasion via Incuabators.
• In Dawn of a New Age: Oldport Blues, Sebastian gains his power to control shadows from the eldritch spirit that came to possess him during the Mass Super-Empowering Event.

Tabletop Games

• Exalted: This is how Infernals are made: a minor demon bearing an Infernal exaltation envelops the body of the Infernal to-be in a chrysalis, as the body and mind of the Infernal adapts to the exaltation. The soul of the demon (designated a 'Coadjutor') is absorbed into the Infernal; it remains sentient (though not always active) and may act as the other voice inside the Infernal's head.
  • Technically all Celestial Exalted have a shard of a god acting as a third soul (normal humans having two in this setting), but most Solars, Lunars, and Sidereals consider it as much a part of themselves as their human higher soul.

Video Games

• Sora from Kingdom Hearts managed to do this twice: the first is with Ventus at the end of Kingdom Hearts: Birth by Sleep, and again with Roxas in Kingdom Hearts II, giving him the ability to Dual Wield.
• League of Legends has Kai'Sa, the Daughter of the Void, a human woman who — after surviving an attempt to rift The Void into her village — bonded with a Voidborn symbiote, forming around her as Bio-Armor and giving her a share of its destructive powers. While the symbiote — like all other Voidborn — wishes to annihilate and consume everything in front of them, Kai'Sa uses its powers to hunt other Voidborn, protecting humanity from newly-spawning Void monsters for decades.
• The Seru from Legend of Legaia grant their human host a variety of superhuman powers as part of a mutual fusion, which may include (depending on the Seru) Elemental Powers, Super-Strength, or flight. In the presence of the Mist, however, this turns to Demonic Possession; the main character's Ra-Seru are immune to this downside.
• Outlast: At the end of The Whistleblower, it's revealed that Miles Upshur became this for The Walrider.
• [PROTOTYPE]:
  • Alex Mercer survived the Blacklight Virus and got powers from it. Or so it seems. It turns out it's not that he survived but that the virus is him. The guy 'hosting' him was also a complete bastard — so spectacularly evil that the flesh-eating super-virus that ate him was an improvement.
  • James Heller, same powers, is also an example; perhaps even a purer one.
• Resident Evil:
  • Jill Valentine in Resident Evil 5, thanks to the anti-bodies in her system from her T-Virus infection in Resident Evil 3: Nemesis, is completely immune to the mutagenic effects of the countless viruses that Umbrella has spawned. Unfortunately, this is also the reason Wesker's Mind Control chest-thing worked on her without killing her.
  • Resident Evil 6 gives us Sherry Birkin and Jake Muller. Sherry still carries the G-Virus in her body from her infection in Resident Evil 2: The vaccine she received stopped her from mutating but gave her a ridiculously sped-up Healing Factor. Jake on the other hand has a variant of the Progenitor Virus in his system which he inherited from dear old dad, which boosts his physical capabilities and makes him immune to the C-Virus — hence his involvement in the plot, as his antibodies are essential to make a C-Virus Vaccine.
  • Resident Evil 7: Biohazard:
    • Zoe Baker is infected with the same mutagenic fungus as the rest of her family, but, for whatever reason, she's exempt from the mind-control aspects of it. This allows her to act as Ethan's Mission Control, guiding him towards escaping the Baker plantation.
    • Also, it's heavily implied that Ethan Winters himself became infected early into the game, but lucked out by getting the physical boosting side-effects — most notably a decent Healing Factor that lets him reattach severed limbs — long before the mind-whammying side-effects started kicking in, allowing him to take down the Big Bad.
  • In Resident Evil Village, an apparition of Eveline reveals that Ethan was revived by the Mold after getting killed by Jack Baker, thanks to his consciousness surviving through the Mold out of sheer willpower. Even though Ethan doesn't realize he's a Revenant Zombie until the end, he takes down the House Lords and the Greater-Scope Villain, bringing an end to their reign of terror while saving his family and avenging the innocent, at the cost of his life. In essence, Ethan is a heroic B.O.W..
• Shin Megami Tensei: Nocturne has Lucifer inject the main character with a parasitic demon called a magatama near the start of the game, transforming him into a half-demon. This becomes most apparent in the Freedom ending, in which the main character saves the world from the destruction all the other endings would condemn it to.
• The spirits in Shining the Holy Ark allow our three main heroes to do things mere mortals couldn't possibly do.

• Skullgirls has a couple of these, most prominently Filia, who plays host to Samson (not the one from The Bible). She combines her own fighting prowess with Samson's Combat Tentacles.
• Revya from Soul Nomad & the World Eaters, host of an Omnicidal Maniac of an ex-psychopomp called Gig. Hosting Gig grants Revya the power of Domination to build his/her own army, at the minuscule price of having a omnicidal monster constantly trying to tempt them into burning the world down for funsies. Subverted in the Demon Path of the game, where Revya turns out to be the worse one of the pair.

Webcomics

• Abbey from Gnoph. Her powers come from the symbiote Scut, who lives in one of her lungs. Gnoph in general work this way, and are implied to be in common use on Abbey's homeworld.

Web Original

• In Worm, every parahuman in existence appears to be an example, as when they get their powers they enter a relationship with a being called a passenger, which gives them access to their powers and makes sure they have the Required Secondary Powers to survive having them.

Western Animation

• Avatars in Avatar: The Last Airbender and The Legend of Korra serve as earthly vessels of Raava the Avatar Spirit, who enables her hosts to channel her (along with the spirits of her former hosts) and harness Elemental Powers.
• In the Futurama episode "Parasites Lost", Fry gets infected with worms. These worms make Fry stronger, smarter, and healthier. The Planet Express crew travel into Fry's body to get rid of the parasites, then Leela stops them because she likes the new Fry better. And then Fry removes the parasites anyway because he wants to know that Leela likes him and not what the parasites made him into.
• In Men in Black: The Series, when a Symbiote attaches to you, the upside is nigh immortality via healing/rejuvenation, Rubber Man-like expansion tied to an epic Shapeshifter Baggage, varying amounts of shapeshifting for yourself, on and off again ability to breathe fire, and a "lay on hands"-ish ability to heal others. the downsides, however, are that you could get attached to an annoying Symbiote and you have 20 hours before you merge permanently.

Real Life

• One theory of the origin of mitochondria. The cellular powerplant organelles have their own DNA separate from the nuclear DNA, and it is similar to some bacterial DNA. It's theorized that these proto-bacteria had superior biochemical processes when it came to metabolism, and in exchange for some form of mutualistic symbiosis, linked with other proto-life that had much bigger cells. They became so intertwined as life evolved that these bacteria just became another part of the cell.

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