Kryptonite Factor / Superman

Superman

Kryptonite Factor in this franchise.

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Comic Books

Comic Books

• Superman is the Trope Namer, with his weakness to Kryptonite (radioactive Green Rocks from his home planet) established back in the 40's. Since then, he's gained a few other vulnerabilities: he has no particular resistance to magic (Depending on the Writer, it may either be a bona fide weakness or that he's just as vulnerable to magic as anyone else, meaning it's a relative weakness for someone immune to almost anything else), red sun radiation can temporarily rob him of his powers, and there's a whole spectrum of colored Kryptonite with varying effects (from Red Kryptonite that causes a random change for 48 hours, to Gold Kryptonite that robs him of his powers permanently). He can still be killed by a huge amount of brute force from a similarly powered being such as Doomsday.
• Something often overlooked is that even ordinary humans are susceptible to Kryptonite radiation, just to a much lesser extent. Additionally, while Kryptonians' natural Healing Factor allows them to recover from radiation sickness almost as soon as they're out of the immediate vicinity of any Kryptonite, exposure in humans is cumulative, as with any radioactive substance. Lex Luthor, who always kept a piece of Kryptonite tucked close to his chest to ensure Superman could never come near him, ends up eventually contracting cancer from it and is forced to build a biomechanical suit to stop it from progressing.
• In Post-Crisis continuity, Gold Kryptonite part is "powerless for 30 seconds", mostly because it couldn't credibly be used for much storytelling otherwise.
• He even has at least three villains — Metallo, Conduit, and the Kryptonite Man — possessing powers that boil down to being Kryptonite. And due to Gold K being Nerfed, minor villain Radion was revised into this in Superman: Up, Up and Away! as well.
• Ironically, Superman is infamous for ignoring Kryptonite through sheer Heroic Willpower. The only thing he is always shown as vulnerable to is magic. This has gives Captain Marvel a firm place in The DCU as a valuable ally for the Man of Steel.
• Brainiac once used a special mix of red and green Kryptonite that gave him a third eye in the back of his head (in Action Comics #275). In order to protect his secret identity, Supes pretended that the kryptonite had addled his brain to make him wear whatever hat is near him.
• Let My People Grow! proves that; not even Superman can withstand an exploding supernova (he needs to wear a special armor suit, and even so he passes out due to the strain); and Brainiac is able to build Kryptonian-killing weapons.
• In Bronze Age storyline Krypton No More, orange sun radiation can temporarily make Kryptonians blind and cut their powers in half. Superman, Supergirl and Krypto learn this the hard way as they are fighting an alien army.
• In Superman vs. the Amazing Spider-Man Lex Luthor uses beam weapons powered with red sunlight to destroy Superman.
• In War World, Martian Manhunter tries to stop Superman using Kryptonite-tipped missiles.
• In Kryptonite Nevermore, all Kryptonite on Earth is turned into iron. Jimmy Olsen notes magic is still a problem, though.
• Subverted in The Immortal Superman, where Superman has become invulnerable to Kryptonite after aging several thousands of years.
• In The Death of Superman, the Eradicator's "Last Son of Krypton" body had an ironic weakness to bright lights. His body, made out of materials from around Superman's tomb, was imperfect and he was unable to see in light. Thus, he is forced to wear a pair of shades to filter the light. In his fight with Steel, Steel is able to punch off Eradicator's glasses, forcing him to flee.
• In Superman vs. Shazam!, since she is vulnerable to magic, Supergirl gets hurt by Karmang's fire spells.
• In The Death of Superman (1961), Lex Luthor kills Superman by strapping him to one stretcher and exposing him to Kryptonite radiation.
• Subverted in Kingdom Come. Spending two decades soaking up rays in rural Kansas and not using his powers has supercharged the Big Blue Boyscout to the point where Lex Luthor believes that a kryptonite-doped nuke wouldn't even be able to muss his hair, much less kill him. The only vulnerability he is shown to have is magic, and he gets a shallow cut from Wonder Woman's sword, which was forged by Haphaestus and is, according to her, sharp enough to carve the electrons off an atom.
• In The Plague of the Antibiotic Man, Amalak creates a yellow energy cocoon around Green Lantern to nullify his Power Ring, and uses Dr. Light's Kryptonite Light to attempt to kill Superman.
• The Leper from Krypton: In at least one instance, though, Kryptonite saved Superman's life. When Kal-El is dying from an incurable disease, two Bizarros try to make his demise quicker and less painful by tossing chunks of White Kryptonite at him. The Bizarros are too dumb to understand that white Kryptonite cannot kill Superman because it has no effect on animal lifeforms...but it does destroy other lifeforms, such like the bacteria which was killing him.
• Played for Laughs in Batman/Superman: World's Finest when while on a date with Robin and waiting for their food Supergirl tries to pass the time by rambling about the different kinds of kryptonite, such as anti-kryptonite which hurts Kryptonians when they're powerless and Bizarro red kryptonite which affects humans instead.
• The Planet Eater Trilogy: When Superman is traversing through the Planet Eater's inner corridors, the humongous machine uses a light cannon powered by red sunlight to weaken him.
• The K-Metal from Krypton was the story which was intended to introduce Kryptonite for the first time (before being rejected by editorial). However, its effects were quite different: Superman merely loses his powers -rather than dying from radioactive poisoning-, and humans gain powers by touching it.

Spin-off Comics

Supergirl

• Supergirl:
  • Kara Zor-El has the same weaknesses as her cousin. Namely: kryptonite, red sunlight, and magic.
  • In the New Krypton storyline, Supergirl faced off against Reactron, an enemy powered by golden kryptonite which nullified her powers. It becomes a plot point in Who is Superwoman? when the titular villain no-sells Reactron's Kryptonite-fueled blasts, thus revealing she's not Kryptonian.
  • In the Red Daughter of Krypton arc, Silver Banshee managed to contain Supergirl for a short while when they fought because her sonic attacks are magic, and Kryptonians are vulnerable to magic. Later on, Kara was weakened when she fought Worldkiller-1 because Earth's atmosphere was poisoned with kryptonite.
  • In the first Supergirl (Rebirth) story, Red Kryptonite -which is non-lethal but does weird things to Kryptonians- turns a Kryptonian into a werewolf. Supergirl's foster mother Eliza Danvers uses a red solar grenade against Lar-On when she notices he speaks Kryptonian.
  • Several times in Elseworld's Finest: Supergirl & Batgirl, Supergirl feels weak and sick without knowing why… until Lex Luthor reveals what Kryptonite is and does to Kryptonians.
  • In The Supergirl from Krypton (2004), Kara Zor-El's pod crash-lands on Earth after spending three decades and a half stuck inside a Kryptonite giant asteroid. Although she survived thanks to her pod's sunlight generators, she suffered from Kryptonite poisoning for over one year.
  • In Supergirl (1982) issue #21, both Super-cousins fight the Kryptonite Man. His power weakens them and hurts them.
    Supergirl: Kryptonite... Cutting through me... like a knife.
  • Kara is vulnerable to magic because it bypasses her natural invulnerability. In Demon Spawn Nightflame's attacks hurt her because that villain is a sorcerer.
  • Last Daughter of Krypton: Kara's attempt to retrieve her pod from Simon Tycho's base fails when she gets knocked out by the bits of Kryptonite stuck to the pod's hull.
  • The Untold Story of Argo City: After being driven crazy by a Kandorian animal's venom, Edna Danvers uses a cache of Kryptonite rocks to attempt to murder Zor-El and Allura.
  • Downplayed in Supergirl: Woman of Tomorrow. When she travels to Ruthye's homeworld, which revolves around a red star, Kara is weakened and can be hurt, but she is still inhumanly strong and tough. Arrows pierce her skin but they do not reach her muscles or vital organs.
  • The Hunt for Reactron, the eponymous villain tries to use Golden Kryptonite to depower his Kryptonian enemies in order to destroy them easily, but he is rendered helpless when Flamebird crushes his chunk of rock.
  • The Girl with the X-Ray Mind: After giving Lex Luthor powers, the Phantom Zone criminals intend to trick him into retrieving a sample of Golden Kryptonite to remove Superman and Supergirl's powers, as well as Luthor's.
  • Subverted in The Strange Revenge of Lena Luthor. Supergirl wakes up in a chamber which supposedly uses high-gravity generators and fluorescent panels which emit red sunlight to nullify her powers by duplicating Krypton's environment. She soon realizes, though, that her kidnappers are gaslighting her and those red lamps have no effect on her.
  • Way of the World features Krallian aliens, who are depowered by a substance called Selenite.
  • In The Supergirl-Batgirl Plot, Superman believes he cannot be harmed by a meteor thrown by Supergirl until his X-Ray Vision tells him there's Kryptonite inside the rocky outside. The fat that "Supergirl" was not harmed by the Green-K clues him in that he is not fighting his cousin but an impersonator.
  • In Supergirl (1984), there is not Kryptonite to found anywhere in the story, and magic takes its place as the tool used by the villain to hurt the Kryptonian hero.
  • "The Super-Steed of Steel": Subverted. Villain Vostar uses a chunk of Kryptonite to murder Supergirl and Comet, unaware that Comet is not from Krypton. Hence, he is downright shocked when Comet remains completely unaffected and flies Supergirl away.
  • Supergirl Adventures Girl Of Steel: Subverted. Kanto tries to stab Kara to death with a Kryptonite knife...which shatters into pieces when it touches her chest because in this continuity -at this point in time- Kara is not Kryptonian but from planet Argo.
  • Played With regarding Power Girl. As a Kryptonian from Earth 2, she's vulnerable to the same weaknesses...on Earth 2. Kryptonite from Earth 1, where she now resides, does nothing to her (and likely red sunlight too). Magic still affects her, but as above, its typically more a 'has no immunity to it' rather than something that makes her weaker. During a time where DC were insisting on keeping Superman as the only Kryptonian, Power Girl was retconned into an Atlantean who had incorrectly believed herself to be Kryptonian, and her powers were now magic in nature. During this time, she was given a weakness to "natural, unprocessed materials" (IE, rocks and trees). Power Trip (2005) explained that this was a result of reality trying to find a 'place' for her after her universe was destroyed, and was attempting to recreate her Kryptonite Factor. Nowadays this period is largely forgotten and ignored.
  • There are at least six colors of kryptonite, each with its own effects — including pink Kryptonite in Many Happy Returns, which can change your sexual orientation.

Other Spin-off Comics

• Legion of Super-Heroes:
  • Daxamites as Mon-El are descended from ancient Kryptonian colonists who intermingled with the native population of Daxam and have similar weaknesses save for Kryptonite itself, instead they're irrecoverably fatally allergic to lead.
  • Superboy (1949) #89 story had Superboy meet Mon-El, an amnesiac with powers like his, who assumed due to this that he was Kryptonian. Near the end of the story, Clark gets suspicious and lobs lead boulders painted to look like Kryptonite at him. Mon-El collapses, and Superboy flies in to accuse him of fakery — but the trauma has brought his memory back; he's a Daxamite, a member of a race similar to Kryptonians, but with a weakness to lead poisoning instead of Kryptonite. To keep him from dying, Superboy puts him in the Phantom Zone, preserving him for a thousand years until the Legion finds a cure in "The Death of Lightning Lad". Later retellings have Clark and Mon-El seeing if Mon-El was a Kryptonian (whose memories were slowly coming back) and Mon-El getting sick after Clark takes out a lead box containing some Kryptonite.
  • Nonetheless, Kryptonite is not a harmless substance. It's more-or-less a radioactive isotope, and can cause harm to anyone if exposed to it for long periods without the proper protection. In some continuities, Lex Luthor develops cancer or goes crazy thanks to repeated exposure. In The Condemned Legionnaires, the female Legionnaires get sick because of involuntary exposure to Red Kryptonite.
  • The Condemned Legionnaires: Subverted. Supergirl reasons Satan Girl's must be Kryptonian given her powerset, so Kara borrows a box of Kryptonite powder to weaken her; though, Satan Girl shrugs it off completely, and later it is her who dumps a heap of Kryptonite rocks on Supergirl to get rid of her.
• Bizarro and his race are vulnerable to blue Kryptonite. In Bizarrogirl, Supergirl and Dr. Light discover they can block Bizarrogirl's powers with light of a K-class star.
  Supergirl: Because I just had an interesting conversation with a brilliant scientist I know. Y'see, a yellow sun gives a Kryptonian powers and a red sun takes them away.
  Bizarrogirl: Bah! Science am boring!
  Supergirl: Ha. You are an imperfect Kryptonian clone, Bizarrogirl, super-powered by a blue sun. Dr. Light theorizes the light of a K-Class star will take your powers away.
• Originally, the blue kryptonite weakness was because Bizarro was a copy of Superman, imperfectly duplicated by a machine. Normal kryptonite had no effect, until Superman thought of using similarly imperfectly duplicated Kryptonite. Just as Bizarro himself has chalk-white skin and a skewed color scheme, the duplicated kryptonite was a different color than the regular stuff.

Films

Films — Animated

• Superman: Doomsday contains an almost amusing example in that even Superman needed Kryptonite to defeat his clone with identical powers. Admittedly, the real Superman isn't quite at full strength at this point.
  Superman: You have all my strengths... and weaknesses.

Films — Live-Action

• DC Extended Universe:
  • Man of Steel:
    • Exposure to Krypton's native environmental conditions weakens and at first even incapacitates Superman.
    • Zod's Kryptonians similarly initially lose control of their powers and pass out while trying to adapt to Earth's native atmosphere.
  • Batman v Superman: Dawn of Justice has Kryptonite discovered among the wreckage of the Kryptonian World Engine near India after the events of Man of Steel. It's explained as a radioactive isotope that actively harms Kryptonian cells. Before a large chunk is found in the Indean Ocean, the most they could find was only good for surgical tools. In contrast to most portrayals, a small amount has no effect just in proximity. Batman develops Kryptonite-laced gas grenades at his best bet at subduing Superman, with a spear as a Finishing Move. This also applies to Doomsday, who is Kryptonian in origin and just as vulnerable to Kryptonite.

Live-Action TV

Live-Action TV

• Lois & Clark: The New Adventures of Superman, setting the tone for most adaptations after it, has red kryptonite affect him mentally instead of the comicverse rules of random one-off effects. Just how dark-side it makes a Kryptonian go depends on the tone of the adaptation, but one thing remains the same: under Red K, Kryptonians are dicks. However, this series also had Red K used to power devices that would affect him in different ways. You get dickishness out of merely putting a chunk of it near him, though.
• Smallville made use of this so often it could get to ridiculous extremes...though, it was a Justified Trope in-universe: Clark's shuttle arrived alongside a massive Kryptonite meteor shower, and Kryptonite became a super-useful Unobtainium that provided a Meta Origin for most villains, with the Kryptonite Factor weakness merely an unknown side-effect. Kryptonite radiation induced metahuman mutations and, until season 4, was seemingly the cause of every superhuman (ergo, every super-powered threat Clark faced was also armed with his one weakness). It was also a great power-source and wonder-drug for any crazy scheme a villain could have, as well as seemingly able to do anything, including provide ink for counterfeit money.
  • Outside of weekly villains, Kryptonite was used as a means to intervene in Clark's relationship with Lana Lang (his original love interest). Yes, Kryptonite wasn't just used to empower villains and weaken his superpowers, but also cock block him, too. Lana had a necklace with a piece of Kryptonite on it, and the effect of it made everyone assume Clark just had crush-induced nausea. Later, Lana became a Man of Kryptonite after absorbing a large dose of it to save everyone, forcing the two to separate and never see each other again.
  • As for Blue Kryptonite as Bizarro's weakness, Blue K was introduced in the series in a storyline totally unrelated to Bizarro - it was a total off-switch for Kryptonian powers but otherwise harmless. However, when Bizarro appeared, he was no misguided, well-intentioned dimwit - he was a Phantom Zone criminal who could possess others, causing Possession Burnout, but ended up creating a new, duplicated body when he tried to possess Clark. He was Clark's opposite in every way, including weaknesses - he was hurt by sunlight and fueled by Kryptonite. This means that Blue K, instead of leaving him no power, gave him the opposite - infinite power, more than he could contain, blowing him to smithereens.
• Supergirl (2015):
  • The DEO revealed early on they have access to actual Kryptonite-based tech, and that general knowledge of it as a Kryptonian weakness is limited. They use it to subdue Supergirl, and J'onn uses a Kryptonite knife against Astra. In "Bizarro", Bizarrogirl is hurt with blue Kryptonite. Kara can also be hurt by other alien materials. Apparently, Superman and J'onn had a falling out due to the fact that DEO has been stockpiling kryptonite for use against evil Kryptonians. They finally reconcile, after J'onn hands the stockpile over to Superman.
  • L-Corp has some synthetic Kryptonite, but it's very unstable and has a tendency to blow up. Lena Luthor and Supergirl have a falling out over this, as Supergirl is absolutely insistent that the Kryptonite be turned over to her, which Lena is not happy about. Supergirl says being exposed to Kryptonite is like being tortured, but Lena says she's just being a hypocrite who doesn't want to be vulnerable. Supergirl later apologizes for her actions, saying that Lena was right, but she feels like she can't be vulnerable because she has the weight of the world on her shoulders.
  • Red sunlight, while not actively harmful, quickly renders Kryptonians as powerless as they were on Krypton. It's one of the DEO's primary weapons against Kryptonians. Flashbacks show that shortly before the start of the series, Lex (who wasn't able to get his hands on Kryptonite) somehow managed to turn Earth's sun red. When Lena insisted that humans can't survive with a red sun, Lex just retorted "neither can Superman."
• In Superman & Lois, Superman has the usual weakness to green Kryptonite and red sun. The DOD has developed a number of Kryptonite-based weapons that come useful when they end up having to deal with evil Kryptonians. Bizarro, being an inverse of Superman, is strengthened by the red sun and green Kryptonite but is weakened by the yellow sun and X-Kryptonite.

Western Animation

Western Animation

• In Superman: The Animated Series, it was originally planned that Supergirl, being in this iteration not from Krypton, but rather the sister-planet of Argos, would not have a weakness to Kryptonite. This is demonstrated in the "Superman Adventures" comic based on the series. By the time of Justice League Unlimited, though, the weakness was firmly in place.

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