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Hot Blade

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Like a hot knife through enchanted assassin bindings.

"Do you see this [knife]? This toasts bread while you're slicing it."

A hot blade is an edged weapon that somehow heats up, adding the thermal energy of its temperature to the kinetic energy of its blow to achieve Absurd Cutting Power. When active, it will usually glow visibly (without losing any of its structural integrity, somehow explanation ) because Power Glows.

Compare Vibroweapon, which uses extremely rapid vibrations instead of heat to enhance its cutting power. A more advanced weapon is the Laser Blade, where the blade is made of Pure Energy instead of just adding (heat) energy to a physical blade. Hot blades are more common in a Science Fiction setting. Its more fantasy-oriented counterpart is the Flaming Sword; a hot blade retains a touch of Playing with Fire while requiring less Willing Suspension of Disbelief.

Usually used with swords, but other bladed weapons are also seen occasionally. A subtrope of Absurd Cutting Power.


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    Anime & Manga 
  • In the battle at the sea in Berserk, Schierke's fire magic was used to turn Guts' Dragonslayer into one of these.
  • Bleach
    • Filler Villain Shusuke Amagai's Zankpaktou has this when its hilt spouts flame.
    • Captain Yamamoto's Bankai, in contrast how his Shikai is a more visually-impressive Flaming Sword, is this, resembling a burnt-black katana that at rest just seems to smoke, along with a full-body flame armor. Both of which are as hot as the sun.
  • Fairy Tail: 100 Years Quest: The Coal Miners guild comes equipped with Alchemic Tools, one of which is a pickaxe that when used consecutively will have its head heat up to increase its power (and in its regular state it can already smash through rock easily). Unfortunately, its user makes the mistake of swinging it at Natsu, where it melts on contact with his body despite him not even using his flames.
  • Fate/kaleid liner PRISMA☆ILLYA: Tanaka can detach her arm and turn it into a red hot sword with incredible destructive power. In fact, it is so hot that Illya cannot pick it up without special protection.
  • In the Gundam franchise, the next step down from beam sabers are heat weapons, the most iconic of which is the Zaku II's heat hawk. Another well-known example is Gundam Sandrock's heat shotels, which become ludicrously huge in Endless Waltz. Usually they cut with a plasma field—like beam sabers, except projected over a surface instead of into the air. This shows in a scene in the original series where a heat hawk is able to briefly parry the Gundam's beam saber
  • In Kuromukuro, Kennosuke, a samurai from the Sengoku Jidai, has a laser-edged katana that he took from an ogre. Recreated (sans laser) by Man At Arms.
  • Lupin III: one episode (also adapted to the anime) implies that the secret of Goemon's impossibly sharp Nagareboshi/Zantetsuken lies in both its temperature: apparently the katana is eeriely hot, which might explain its ability to cut through anything.
  • In One Piece Enel does a variation by using his electric powers to turn his trident into molten metal in order to burn Luffy, who's immune to direct attack by Enel's lightning. He also uses it to quickly reshape said trident (it was originally just a golden staff).
    • There's also Shura from the same arc who uses a Heat Javelin, a Jousting Lance with a Heat Dial inside it that lets him stab and burn things simultaneously.
  • Yaiba has Gold, who can apparently heat up his gargantuan Sinister Scimitar somehow. However he does this once.

    Comic Books 
  • In Supergirl story Demon Spawn, the titular heroine faces up to Nightflame, a villain that can heat up her huge magic sword.
  • In Superman vs. the Amazing Spider-Man, Lex Luthor forges a sword imbued with superheated red sunlight that can hurt Superman.
  • Thermal swords, which presumably were super-heated based on the name, were the favored melee weapons of the Dinobots in Marvel's run of The Transformers G1 comics incarnation.
  • When Wolverine is brought back to life in the beginning of the Marvel: A Fresh Start launch, he's given the New Superpower of superheating his claws, at the expense of diminishing his healing factor and tapping into his berserker side. At the end of Return of Wolverine, when Wolverine locks away his berserker side, it also disables the superheating claws.

    Fan Works 
  • City of Chains has Everburn, Lucien's two-handed sword. Despite the name, it is this and not a Flaming Sword.
  • Tech 10 Rebooted has the Pyronaut Blade, an alien weapon that can pierce through most armor when at full temperature.
  • XCOM: RWBY Within has Blake carrying a knife with a low-power laser in the handle, which heats the blade and allows it to more effectively penetrate armor and hardened skin. note 

    Film — Live-Action 
  • The Hitchhiker's Guide to the Galaxy (2005) has a throwaway gag about a knife that toasts bread while slicing it.
    • Better yet, it's basically a tiny lightsaber, and the filmmakers had to pay Lucasfilm royalties to use the appropriate sound effect.
  • In Pirates of the Caribbean: The Curse of the Black Pearl, after Will uses his sword to jam the door of the smithy and cut off Jack's escape route, he grabs a replacement out of the forge. It looks impressively glowy but doesn't last very long since Jack uses his handcuffs to snag the blade and send it flying; fortunately there are plenty more on the racks.
  • In Rebel Moon, Nemesis wields two heated blades, one on each arm. Wielding these blades requires to sacrifice both hands due to the heat, and so she has cybernetic hands to handle them.
  • Optimus Prime from the Transformers Film Series uses some of these to cut Decepticon's heads clean off.
  • In The Wolverine The Silver Samurai was able to cut Wolverine's admantium-coated claws with a superheated Adamantium sword. Since Adamantium suffers from a Like Cannot Cut Like rule, presumably the intense heat melts the claws off.

  • In Codex Alera many of the High Lords combine fire and metalcrafting to heat their swords, because a bleeding wound can be watercrafted better easily enough, but a cauterized wound is unhealable. Since this causes their swords to shine brightly, they also use them to send signals and challenges that can be seen across the chaos of a battle.
  • The Warpsword of Khaine from Malus Darkblade is said to feel like it just came out of the forge, and it burns whatever it hits.
  • In A Song of Ice and Fire, Azor Ahai was a legendary hero who worked for one hundred days and nights to forge a sword before driving it through his wife's heart; combining her soul with the steel of the sword and creating Lightbringer, the Red Sword of Heroes. The sword is described as always being warm to the touch.
  • Steel Crow Saga: Metalpacters can use their Extra-ore-dinary powers to heat metal red-hot with a touch, which they use in combat to enhance their bladed weapons. Their powers also maintain the blade's strength and let them hold it safely.
  • In Clay and Susan Griffith's Vampire Empire series, it is 20 Minutes in the Future and remnants of a steampunk British Empire barely escaped a vampire apocalypse. Among the weapons used by humans against the vampires is the Fahrenheit Blade. These are blade weapons, including khukris, that have a special sheathe which will coat the steel blade in volatile chemicals. This heats the blade to extremely high temperatures and are more devastating against the heat-sensitive vampires than regular swords.

    Live-Action TV 
  • Supergirl (2015): Vartox wields a red hot axe that can cut a Kryptonian. Ironically, Supergirl destroys it by blasting it with heat vision until it can't take the strain and explodes.
  • The Ultra Series have multiple examples where the main ultra of the show can summon glowing, energy blades coated with superheated plasma which can slice apart kaijus.
    • Ultraman Gaia and his co-star, Ultraman Agul, can both summon superheated energy blades. In one episode Gaia uses his blade to slice a kaiju into chunks.
    • Ditto for Ultraman Mebius and Ultraman Hikari, whose wrist blades glows with superheated plasma and have more than once bisected kaijus into two pieces.
  • Ultraman Zero: The titular Ultra's Zero Twin Sword, created by merging the Zero Sluggers with energy of the Plasma Spark. It glows with plasma energy and makes the Zero Sluggers even sharper than it already is, allowing Ultraman Zero to slice apart enemies like butter.

    Tabletop Games 
  • 1001 Science Fiction Weapons for D20, by Plain Brown Wrapper Games, also has a section on superheated blades. Various blades are used, including a scythe; though unlike the supercooled weapons available in the book, the superheated scythe is not useful for non-combat reaping of wheat as the crop is set on fire. It is stated that if you see one of these hanging on the wall, you're probably dealing with a villain.
  • Call of Cthulhu supplement Cthulhu Companion, adventure "Valley of the Four Shrines". The East shrine is dedicated to Cthugha, a deity made of fire. A sword found in a secret room can be made to glow yellow-hot, which will do damage to creatures vulnerable to fire.
  • Dungeons & Dragons is full of these. As well as (among others) lightning and cold versions. Not restricted to bladed weapons, though...
  • Exalted: A Malfeas charm turns a blade too burning hot to be wielded, forcing your enemy to either drop it or suffer lethal damage. Another version of this charm targets armor instead... and it's not easy taking off your armor during a (heh) heated battle.
  • In Nomine: While not a bladed weapon per se, Mjolnir's head glows red-hot when swung. It deals quite a lot of damage, but also severely harms its holder unless it's grasped using the magic gauntlet Jarngreipr.
  • Obsidian Age Of Judgement: One of the expansion books has a gun version of this trope. Normally flamethrowers are the weapons of choice against the undead, unfortunately they come in only one size and don't do that much damage compared to the larger machine guns. So a new weapon was invented, it's a gun with a mechanism that separates the bullet from the casing. It then superheats the bullet until it's almost molten and then the casing with charge is fired. So the super-hot bullet is shot out at high velocity and will rip up standard targets, while also incinerating enemies that are bullet-resistant.
  • Warhammer: In the various settings, many swords are depicted as glowing red-hot, even when some flames might flicker depending on the artist, verging into Flaming Sword territory.

    Video Games 
  • The (in)famous Pyrotechnic Axes in Arcanum: Of Steamworks & Magick Obscura presumably work this way. They dole out a hefty amount of fire damage in addition to their base damage. They're one of the strongest weapons in the game, assuming you're a melee-based technologist.
  • Though they are not technically swords, the hooks thrown by Spider Splicers in the BioShock games are glowing red hot. They are probably heated by plasmid use on the part of the splicers.
  • In the VR game Blade and Sorcery, you can apply fire magic to a sword you are holding to turn it into a glowing blade that can slash and stab through even knightly plate, for instant Armor Is Useless.
  • One of the bosses from Chrono Cross uses a Steampunk version (a Nigh-Invulnerable, Humongous Mecha), but this is technically a fantasy setting.
  • Nero's Red Queen from Devil May Cry has a special mechanism inside it; the sword has a gasoline fuel inside, and the sword can be revved; when doing so, it sprays out the fuel to the blade as well as igniting it, making the blade glow hot red.
  • Fallout: New Vegas:
    • The Cosmic Knife from the Dead Money expansion can be made into this after being warmed by a heating pad, since its Saturnite material somehow retains heat for a ridiculous amount of time. Such superheated blades have an x5% critical hit chance multiplier and set foes on fire, but unlike the Cosmic Knife (clean) variant you can make with Abraxo-brand cleaning agent, the superheated version is still covered with Cloud residue and thus has less durability.
    • Similarly, the Saturnite Fist from the Old World Blues DLC can be given to the Toaster in Big MT and made superheated, glowing red-hot and setting enemies you punch on fire. One wonders how you don't burn your own hand while wearing it.
  • The Final Fantasy XIV version of the Gunblades is this principle applied to the Vibroweapon mechanism of the Final Fantasy VIII models. The aetheric cartridges the weapon uses are "fired" to flash-heat the blade and increase its cutting power. In fact, guns are an imitation of this technology that was converted to launch projectiles instead, and the name of these weapons were derived from the warriors who first wielded these weapons: the Gunnhildr's Blades.
  • In Guilty Gear, Sol Badguy's Fireseal (and its upgrade, Junkyard Dog) allows him to channel his flame powers better. It also allows him to cut with it, despite the blade part being a blunt rectangle.
  • A variation from Half-Life 2: an electromechanical crossbow that launches red-hot rebar rods.
  • The Henry Stickmin Collection has a subversion in Completing the Mission on the Valiant Hero path. Charles tells Henry to press a button on his helment to dispense a superheated knife to cut into the Toppats' space station hull, but it drifts away before he can grab it, leading to a FAIL.
  • The Legend of Zelda: Breath of the Wild blurs the line somewhat between this and Flaming Sword. The Flameblade (along with the Great Flameblade and Flamespear) glows red when carried and puts out enough heat to keep Link warm and even melt ice. But when used to attack, it emits a burst of fire that can ignite anything flammable in its path. Most players use it as a convenient way to start campfires.
  • The Super Spicy Knife in the Like a Dragon series is red all over and whoever gets cut by one gets set on fire.
  • The Omni-blade in Mass Effect 3, the hologram is so the user doesn't accidentally burn themself.
  • In Metal Gear Rising: Revengeance, LQ-84-series UGs can throw superheated knives that are able to penetrate (and partially melt) stone and metal. Perhaps notably, Sam's sword also has a distinct red blade but isn't a Hot Blade; just an exceptional Vibro Weapon. Sundowner's weapon also seems to count, as visible heat and steam can be seen as he slowly slices across the President's neck in the intro.
  • Red Alert 3: The Imperial Warrior's katanas seem to work like this, as they have a cooldown but instakill any infantry in their way.
  • In Rocket Knight Adventures, Sparkster the Rocket Knight sheathes his sword in his jetpack, and several of his stronger attacks have his sword glowing with a blue, orange, or red flare indicating that he traps the heat in his sword. One of the powerups he can find in RKA 2 upgrades him outright to a Flaming Sword.
  • In Strider, Hiryu's Cypher uses plasma to achieve this effect.
  • In Subnautica, you can use a Modification Station to upgrade your trusty Survival Knife into a Thermoblade, which doubles its damage (not that you particularly want to get in a knife fight with a leviathan) and instantly cooks any edible fish you whack with it. The downside is that the weapon is wholly ineffective against any lifeforms adapted to live in lava, such as the ones in the Very Definitely Final Dungeon.
  • In Super Robot Wars Compact 2, the Alt Eisen carries a "Heat Horn" mounted on its head and functions like the Heat Hawk of the Zaku II. When it's rebuilt and upgraded into the Alt Eisen Riese, the weapon is turned into the "Plasma Horn", with an additional feature of Shock and Awe.
  • Warframe has the Heat Sword, Heat Dagger, and Dual Heat Sword (sword+dagger combo), which do fire damage on some of their special attacks. All of them have visibly red-orange blades with glowing segments. Grineer melee weapons like the Cleaver, Machete and Sheev also have red-hot powered blades.
  • The Thermic Lances in X-COM: Terror from the Deep are a combination of Hot Blade and Vibroweapon, and are pretty effective against the Demonic Crabs. note 
  • The final upgraded blades for the Rangers in XCOM 2 are hot enough to set enemies alight sometimes.
  • In Yandere Simulator, Yandere-chan has the option to heat up a knife blade with blowtorches. As of right now the effect is more cosmetic than of practical use... unless you want to turn it into a Flaming Sword instead.

    Web Original 
  • Keyleth attempts this in one episode of Critical Role, using Vax's daggers as the focus. Unfortunately, due to a misunderstanding about the effects of the Heat Metal spell and an aversion of Convection, Schmonvection, the extra damage is done to Vax.

    Western Animation 
  • Sunforge Blades in The Dragon Prince are Sunfire Elf artifacts enchanted to stay as hot as the moment they were forged. Even a dagger-sized one can cut through steel and solid stone with ludicrous ease, and wielders need to store them in specially-enchanted sheathes, lest they themselves be set on fire. Just about the only thing a Sunforge Blade can't cut is another magically-imbued item like an Assassin's Binding.
  • My Adventures with Superman: Slade Wilson wields two katana that are hot enough to burn Superman's skin.
  • SheZow's Evil Twin SheZap has a curling iron that combines this with Laser Blade.
  • Steven Universe: The fusion Obsidian wields an absolutely enormous and extremely sharp sword made out of lava. It proves capable of cutting through starships with ease.

    Real Life  
  • Heated blades have been used for crude amputations to cauterize and disinfect the wound.
  • In real life, this is Awesome, but Impractical. As any blacksmith or metalworker can attest, steel loses its hardness the closer it gets to its melting point.
    • Special metallurgy that can mitigate this has existed since the 1930s or so with "high speed steels" - which were developed in response to modern industrialized machinery (like drills, end mills, ect.) becoming more capable and having higher RPMs. So, instead of finding roundabout solutions to the problem of drill bits heating up and dulling because of it, high speed steels were developed which simply retain their regular hardness at high temperatures with addition of molybdenum, tungsten and cobalt. With some of these steel alloys, operating temperatures in excess of 500°C (almost a thousand degrees Fahrenheit) are possible. More if you're willing to sacrifice some hardness. To make things even better for potential application of this, high-speed steels are popular in high-end cutlery and knife making. Steels like CPM M4 are becoming extremely popular because of how "hard" the steel can be ran (usually well above 60 HRC, which is about where most steels start to top out at before becoming too brittle - some alloys can almost reach 70 HRC, which is nearly on par with the higher end of ZDP-189) and it's wear resistance. Steels like CPM M4 and CPM Rex T15, especially, on a properly forged knife would seem like space voodoo magic to someone unaware that such capabilities were possible. Heating one up, however dangerous and unwise that would be to use, is certainly possible.
      • However, As this experiment tells, while a Real Life Hot Blade may look impressive in some stunt, cutting power is not much increased, even with incandescent 1000°F knife.
      • Good luck trying to push-cut through a 20oz plastic soda bottle (with the cap still on, no less) with an ordinary kitchen knife that isn't heated enough to weaken the plastic you're push-cutting into... Or without using hundreds of pounds of force behind the cutting edge (which, while the person in the video was pushing with enough effort to cause straining, if the same blade in question was NOT heated they would not be doing much or any cutting at all like what you see here). It's not so much increasing the cutting power as it is making what you're cutting easier to cut into... because it's melting.
  • Thermal lances use superheated steel or aluminum to cut through just about anything. But here it is not a sharp edge or point that does the cutting. It is the metal burning in pure oxygen.
  • There once was a practice called "Blood Tempering," in which a red-hot blade is inserted by stab-wound and/or anally into a slave or prisoner of war, as it would cool the sword at body-temperature. This supposedly made the blades much stronger, and always killed the stab victim in practice. "There was once" is the phrase because no one does it anymore and even in the past it was uncommon. This is because the human body has such a wide variety of liquids and materials, it invariably created a blade with a poor, uneven temper that shattered easily. It was rarely maintained for any length of time in any culture, despite a moderately common myth.
  • Hot knives can be used to smoke drugs (generally cannabis, but sometimes also the more pastelike smokable opiates) in a process called "spotting." The tips of two knives are heated, and a small quantity of the marijuana (or what have you) is first rolled into a little ball and then pressed between the knife tips. This creates a massive quantity of smoke, which is then inhaled (possibly through a funnel called a spottle).
  • Downplayed with tools used to cut synthetic rope, which uses heat but doesn't glow. A blade is electrically heated hot enough that it can be used to cut through a rope while melting the cut to seal it and prevent the rope from unbraiding.
  • Extremely downplayed, but technically the spirit of the trope is often invoked on ice cream; running the serving utensil under hot tap water and wiping beforehand makes cutting through the frozen dairy much easier. And, of course, the origins of the alternate trope name, "like a hot knife through butter", can be applied the same way.

Alternative Title(s): Like A Hot Knife Through Butter