The Henshin Hero is a variation or subtrope of the Superhero in which super-powered characters only have their special powers some of the time. A Henshin Hero has distinct normal and powered "forms," and needs to actively switch between the two. In essence, the character's powers are all turned off while they are in their Secret Identity.
Henshin Heroes often have a special item which they use to change into their heroic form. These items are usually activated by a command phrase, triggering a Transformation Sequence.
The transformation is frequently accompanied by a costume change. This gives the trope some overlap with Clothes Make the Superman: many male Henshin Heroes wear power-armor of some kind, and their transformation allows them to don their armor almost instantly. Bonus points if the change of clothing is the only outward difference, but nobody notices.
The name comes from the Japanese term for the trope, henshin (literally meaning "change body" but more practically translated as "transformation" or "metamorphosis" ... and not to be confused with the Shapeshifting or Metamorphosis tropes).
Superpowered Alter Ego is when this trope meets Split Personality. Magical Girls and Magical Girl Warriors are a subset of the Henshin Hero that are (usually) targeted toward the Shoujo demographic.
- Metro Manners: Super Kind is an ordinary transit rider who becomes a superhero (complete with costume and Transformation Sequence) after saying a key phrase when she sees bad behavior on the Metro. She seems to have New Powers as the Plot Demands in order to combat Rude Dude.
- Older Than Television: Captain Marvel, who debuted decades before He-Man or the Japanese heroes, making him the Ur-Example of all transforming heroes. He's normally a powerless little boy (or early teen) named Billy Batson, but when he says "Shazam" (an acronym of the names of six mythological figures), he's transformed into a powerful Flying Brick. Cap's supporting cast featured a lot of these, including Mary Marvel, Captain Marvel Jr., Hoppy the Marvel Bunny, and the Lieutenants Marvel, as well as a lot of Henshin Villains, like Black Adam, Ibac, and Sabbac. Later it was revealed that even the wizard Shazam himself was a former Henshin Hero thousands of years ago when he was Jebediah of Canaan, who transformed into The Champion by saying the magic word "Vlarem". Most of those characters were retconned out with the New 52 reboot in 2011, but the current version of Billy Batson still says "Shazam" to transform from a normal boy into a superhero (albeit one with somewhat different powers).
- Miracleman (originally and still sometimes Marvelman - see MM's own page for the convoluted legal history) was a direct homage to Captain Marvel, created while the latter was in the middle of his twenty-year publishing hiatus, and transformed by speaking the word "Kimota" ("atomic" backwards, more or less). He likewise had two teenage sidekicks, Young Marvelman/Miracleman and Kid Marvelman/Miracleman, who transformed by speaking their mentor's name.
- Blue Beetle, especially the first (Dan Garrett used a mystical scarab to transform into a superhero) and the third (Jaime Rayes, who uses the same scarab, now revealed as an alien artifact, to turn into a power-armored superhero). The second Blue Beetle, Ted Kord, was never able to get the scarab to work for him, so he is not an example.
- Iron Man, to an extent. Basically, it depends on the version of the suit. Sometimes it'll form itself around a bodysuit that goes beneath it. And sometimes it has a compact form like the suitcase suit, though he does have to step in or pull it around him while it's partially formed. Iron Man fully qualifies with the "Bleeding Edge" armor, which is stored within Tony Stark's body and called out mentally at need.
- Wonder Woman Vol 1: For a time Diana no longer had her powers when not "transformed" into Wonder Woman. (This was also how it worked in her TV series)
- Ghost Rider counts as this given that Johnny Blaze (and other riders) had a normal human form and a Spirit of Vengeance form.
- X-Men: Colossus is large and buff-looking in his human form, but only superhumanly strong and tough in his metallic form. He's still strong in his human form, but only "normal human who pumps iron" levels of strong.
- The Mighty Thor and Dr. Donald Blake are a variation on this - the difference being that Thor is the original and Blake was a mortal form Odin forced upon his son as a test. Most other wielders of Mjölnir or passable replicas thereof also fit under this trope more-or-less. Including but not limited to Storm when she got repowered by Loki, Beta Ray Bill (albeit he is also a super soldier; he was already strong but gets a lot stronger when transformed), Thunderstrike (both of them), and the new Thor Jane Foster.
- The Flash Jay Garrick and Green Lantern Alan Scott of Earth 2 gained their powers and costumes via mystical sources. As such, their costumes only appear when they use their powers.
- Depending on who's writing the DC character The Spectre, he may or may not have some form of this. The older stories treated him as a guy who was returned from death and could, when he wanted, take on a ghostly form with mystical powers. Most later writers treat the Spectre and the human host it's associated with as separate characters, with how much control the host has when in Spectre form being highly variable. In the Ostrander run the two were separate to the extent that Corrigan didn't have a "Spectre form"; the Spectre essentially lived inside him (but could temporarily leave and act independently).
- Ultra Boy of the Legion of Super-Heroes had a slight variant. He had all the powers as Superboy had, but only one at a time; he could be either super-strong or invulnerable, but not both at the same time.
- The protagonist of Dial H for Hero had an alien artifact that would transform him (or her) temporarily into a superhero-ish sort of thing. The form and powers were random, though with some thought they were always applicable somehow to the current problem.
- The Incredible Hulk: The Hulk is theoretically this; in human form Bruce Banner is just a regular guy (though fairly smart), while in Hulk form he's extremely strong and tough, but he's also really stupid (usually). Because the comic is called The Incredible Hulk instead of The Average Banner, he tends to spend about 90% of the time as the Hulk, with the writers before the 00s reverting him to human form to have him angst for a while. Since Planet Hulk and its follow up stories, Banner has been given more control/a partnership with Hulk's personality that allows them to transform back and forth at will, with Green Hulk taking on a more intelligent form of speech, making them more a classical version of the trope, though both still see each other as the "other guy" to some extent.
- The Amazing Three of Jackpot were three ordinary children given the power to transform into the heroes Oakman (Exactly What It Says on the Tin - a super-strong flying man made out of oak), Tanya (a flying woman with the ability to shoot lasers from her finger tips) and the Blue Wizard (who couldn't fly, but did possess no end of magic powers) in order to battle the evil alien Vogler.
- The Golden Age Fury of the All-Star Squadron sequel series The Young All-Stars transforms into her superpowered form (complete with bulletproof armor) just by thought alone (or sometimes when she gets angry).
- Ms. Marvel (1977): Starting out, Carol Danvers was one of these, having superpowers in her "Ms. Marvel" identity and none as Carol, with the additional wrinkle she didn't know this - Carol and Ms. Marvel were separate personalities, with Carol gaining a few centimeters and a different haircut whenever she became Ms. Marvel. After a while, the two became aware of one another, and the line between them starting blurring together.
- The Pieces Lie Where They Fell: Omake character Reel, AKA Kamen Rider Skull II, who became one after gaining the powers of a Kamen Rider in his backstory.
- A Place in My Dreams: One of Kirito's Authorities, [Avatar of Dreams], allows him to manifest a strong mental image of himself (a dream) into reality like armor. He first uses it to transform into his Sword Art Online Avatar, but it is capable of bringing any form he can sufficiently imagine into reality too. Such as avatars from other games.
- Deconstructed in The 10 in Ben, where the stress of being a Kid Hero and the confusion of having multiple different 'forms' results in Ben developing multiple personalities. The catalyst for this was his transformation into Grey Matter, as a way for his brain to process having knowledge and understanding he simply did not have before.
- In the Moonwalker movie and games, Michael Jackson can morph into a sportscar, a robot (aka the Jacksonator), or a space fighter plane, with the power of a Wishing Star.
- Tony Stark in Iron Man, just like the comics. As he continues to advance the technology, donning it becomes easier every time, going from needing a lot of machinery to assemble and disassemble it around him in the first to having the suitcase suit in the second to each piece flying into place on its own with so long as he wears certain arm devices to summon it in The Avengers to basically doing a henshin pose that it responds to (not quite perfected) in the third. Particularly noticeable in the third film, where the climax involves him alternating between suits in quick succession, each opening, letting him in, and resealing around him as needed even in midair. Avengers: Infinity War takes it even farther - nanites stored in a chest-worn device pour around him to form the suit with a touch. That’s as close to a Toku hero as you’re getting without having him shout “It’s morphin’ time!”
- The titular Behemoth of The Behemoth is Roger's alternate form, a giant figure armored with coagulated blood and adorned with horns.
- This is the most common superpower (not that one) in Super Powereds. Most Supers are Shifters, requiring them to turn into their alt-form to activate their powers. In rare cases (such as with Hershel/Roy), this crosses with Superpowered Alter Ego. There are a number of Shifter-type Supers at Lander, including one of their gym teachers, who turns into a robot.
- In one novel of The Shadow it was declared that The Shadow had most of his powers (i.e. his ordinary powers) in any of his forms, including Lamont Cranston. However, only when fully garbed as The Shadow in his cloak and hat, could he "cloud men's minds".
- Kamen Rider was the Trope Namer and the Trope Codifier. Most Kamen Riders have "Henshin!" as the changing command.
- This trope is also a staple of Super Sentai series, as well as their American Power Rangers adaptations. Typically a Sentai team would all activate their Transformation Trinkets to do a group transformation, before striking out in a cool pose.
- Metal Heroes, being from the same folks behind Kamen Rider and Super Sentai and running from 1982 to 1999 (with some movie revivals in the 2010s). Generally, they saw the hero donning a suit of Powered Armor to fight against the bad guys.
- The Ultra Series is the Ur-Example for Japanese Tokusatsu. In every series, an ordinary guy uses a Transformation Trinket to become a gigantic alien warrior of light in order to battle kaiju and sizeshifting aliens. Unlike the previous three major franchises, it's not produced by Toei, but Tsuburaya Productions.
- Kikaider is a Ridiculously Human Robot who assumes a more robotic fighting form by chanting "Switch On".
- Inazuman had two henshins Goro needed to perform before assuming the titular form, first by shouting "Goriki Shourai" (Summon Mighty Power) to become the larvae-like Sanagiman. After building up enough energy, Goro could then shout "Chouriki Shourai" (Summon Super Power) to become Inazuman.
- Choujin Bibyun was about a trio of humans each imbued with a demon, giving them the power to assume superhuman forms to fight against evil Youkai.
- There was a Japanese Spider-Man series that turned him into a Henshin Hero, rather than the usual change of costume. He even got a Humongous Mecha to battle the Monster of the Week whenever it turned giant-sized! Yeah, it was that kind of show.
- Many American tokusatsu adaptations (most of which came around the same time). Asides from Power Rangers (which started the craze), we have VR Troopers, Masked Rider, Superhuman Samurai Syber-Squad, and Big Bad Beetleborgs. There was also Kamen Rider Dragon Knight, which came sometime after the trend had faded out and left only Power Rangers standing.
- Ema in the Japanese drama Sh15uya had a henshin ability, but it was never really explained.
- The Lynda Carter Wonder Woman series. Diana Prince had to spin (along with an act of will, so she couldn't change accidentally) to transform into Wonder Woman in order to access her powers.
- Warrior of Love Rainbowman has no henshin device; instead he repeatedly chants "Anokutara Sanmyakusanbodai" (Supreme Correct Wisdom) to transform.
- BIMA Satria Garuda has Ray, who with the red Power Stone and the changing command "Berubah!" (change) transforms into the eponymous hero.
- Appropriately for something that grew out of Champions, the superheroic tabletop game, the HERO system has a Power Limitation called "Only In Heroic Identity." It's not worth many points, but it essentially means that the character has an alternate form and that the power in question only works in his superheroic form, thus opening the possibility that the character be trapped into his normal form and denied access to his superpowers.
- The "normal identity" drawback in Mutants & Masterminds means that the character has a non-powered civilian form. Both Freedom City and Halt Evil Doer! have Shazam Expy characters (Megastar and Ultimatum respecively) which use this.
- Big Eyes, Small Mouth has a specific version of Form Change that grants the user a super-powered form.
- Legend includes a set of abilities called "Vigilante," which allows the user to summon armor and power buffs with a shouted command (Transformation Is a Free Action for Vigilantes).
- Played with in the various World of Darkness games.
- Averted in most games. You're, for the most part, always a monster at all times, and can do a variable job hiding it.
- Downplayed in Werewolf: The Forsaken, where human-form Uratha enjoy slightly increased physical durability and supernatural perception, but most of their power is in their Hybrid forms. Just take care with your rage.
- Played Straight in the fan game, Princess: The Hopeful, due to its Magical Girl inspirations.
- Vigilantes in even the Badass Normal builds, have distinct abilities in their social and vigilante identities. The Magical Child even gets a Transformation Sequence.
- The Aegis from Dreamscarred Press can be played as transforming heroes.
- Little Red Goblin Games' Gonzo 2 has a Pathfinder class explicitly called the Henshin Hero, along with a Magical Girl class, the aptly-named Magical Girl or Magical Boy. (Mechanically, they're very similar, but the Henshin Hero specializes in physical attacks while the Magical Girl/Boy specializes in magic)
- Future Card Buddyfight has the Transform keyword. It's unique to the Toku-style Superheroes (or their counterparts the Dark Heroes), and is flavored this way. Monsters with this keyword may be equipped as though they were items, effectively turning you into a Henshin Hero.
- In the "Supertoon" setting for Toon, the Multiple Forms schtick gives you this. Although if you want a really weird character you can give both forms superpowers.
- In El Goonish Shive, Elliot's magic lets him fly and gives him heightened durability and an accelerated healing factor, but only when using a particular spell that also requires him to turn into a woman. He has other superhuman abilities that can be used without transforming, though.
- Karin-dou 4koma features a Henshin Hero youkai—not a youkai who is a Henshin Hero, mind you, but rather the concept of "Henshin Hero" personified. He only makes two brief appearance with some friends, though, and doesn't appear as anything other than an ordinary schoolboy.
- Sheena, in Kid Radd. Complete with a parody of an anime Transformation Sequence: "Magical Maid Robo Sheena!"
- Atop the Fourth Wall:
- Linkara turns out to be one of these. He transforms with a classic Mighty Morphin' Power Rangers morpher into his jacketed-hatted form, albeit usually just before the show begins.
- And thanks to the Power Rangers Zeo Zeonizer he can transform into his upgraded White Zeo Ranger Form
- Better still, he also has a gold Power Morpher with a Dragon coin in. Which lets him become the Green Ranger.
- In an anniversary episode, he uses cards and the Power Rangers Megaforce Morpher switch between different outfits.
- The Apollo Z. Hack Reviwarverse Saga features the eponymous hero and his nemesis possessing R-Units (which look surprisingly like Kamen Rider Dragon Knight belts) which let them "Rev Up" to transform into Kamen Rider like super powered forms called Revuers.
- LWAAS uses Jo's Manga: Mecha Girl. The main character Yukasa,Takes off her clothes,just in her Underwearof Power underwear pressing the button In the center of her bra Transformation Trinket and transforms into Mecha Girl! Power Armour.
- Eric Draven, from Mall Fight. He started off as a Green Ranger, moved onto becoming Kamen Rider Black, and now transforms (actually saying "HENSHIN!") into a fusion between Kamen Rider and Ghost Rider.
- JewWario used to transform into "The Warion" but has now been upgraded into the Fami-Kamen Rider, a Nintendo/Famicom-themed Kamen Rider with powers based on 8-bit video game sprites (and a Rider Belt that's a portable Famicom unit).
- Inverted with Oingo in Vaguely Recalling JoJo. His Stand, Khnum, is based off the Rider belt and he uses it for assassinations.