[[quoteright:259:http://static.tvtropes.org/pmwiki/pub/images/Red_Hot_1926.jpg]]
[[caption-width-right:259:[[{{Pun}} Too hot to handle]].]]
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 AbsurdCuttingPower. When active, it will usually glow visibly (without losing any of its structural integrity, [[MST3kMantra somehow]]) because PowerGlows.

Compare {{Vibroweapon}}, which uses extremely rapid vibrations instead of heat to enhance its cutting power. A more advanced weapon is the LaserBlade, where the blade is ''made'' of PureEnergy instead of just adding (heat) energy to a physical blade. Hot blades are more common in a ScienceFiction setting. Its more {{fantasy}}-oriented counterpart is the FlamingSword; a hot blade retains a touch of PlayingWithFire while requiring less WillingSuspensionOfDisbelief.

Usually used with [[ILikeSwords swords]], but other bladed weapons are also seen occasionally. A subtrope of AbsurdCuttingPower. Unrelated to the idiom "like a hot knife through butter"... though hot blades may, indeed, cut through things in such a manner.

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!!Examples:

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[[folder: Anime and manga ]]

* In the ''Franchise/{{Gundam}}'' franchise, the next step down from EnergyWeapons like beam sabers is heat weapons, the most iconic of which is the [[Anime/MobileSuitGundam Zaku II's]] heat hawk. Another well-known example is [[Anime/MobileSuitGundamWing Gundam Sandrock's]] heat shotels, which become [[{{BFS}} ludicrously huge]] in ''[[TheMovie Endless Waltz]]''.
** At one point in [[Anime/MobileSuitGundam the original series]], a heat hawk is able to briefly parry the Gundam's [[LaserBlade beam saber]], which is formed from superheated plasma. [[FridgeBrilliance Because a heat hawk blade would by necessity have a higher melting point than the Zaku's armor.]]
* In the battle at the sea in ''{{Berserk}}'', Schierke's fire magic was used to turn Guts' Dragon Slayer into one of these.
* ''Manga/{{Bleach}}''
** FillerVillain Shusuke Amagai's Zankpaktou has this when its hilt [[FlamingSword spouts flame]].
** Captain Yamamoto's Bankai Seems to be this, along with a fullbody flame armor. Both of which are ''as hot as the sun''.
* In ''OnePiece'' [[ShockAndAwe Enel]] does a variation by using his electric powers to turn his trident into molten metal in order to burn [[RubberMan Luffy]], who's immune to direct attack by Enel's lightning.
* ''{{Yaiba}}'' has Gold, who can apparently heat up his gargantuan SinisterScimitar somehow. However he does this once.

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[[folder: Fan Works ]]

* ''FanFic/Tech10Rebooted'' has the Pyronaut Blade, an alien weapon that can pierce through most armor when at full temperature.

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[[folder: Film ]]

* Optimus Prime from the ''Film/{{Transformers}}'' movies uses some of these to cut Decepticon's heads clean off.
* In the first ''PiratesOfTheCaribbean'' film, after Will [[ThrowingYourSwordAlwaysWorks 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; fortunately there are plenty more on the racks.
* ''Film/TheHitchhikersGuideToTheGalaxy'' has a throwaway gag about a knife that toasts bread while slicing it.
* In ''Film/TheWolverine'' The Silver Samurai was able to cut Wolverine's admantium-coated claws with a superheated Adamantium sword. Since Adamantium suffers from a LikeCannotCutLike rule, presumably the intense heat melts the claws off.

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[[folder: Literature ]]

* The Warpsword of Khaine from ''Literature/MalusDarkblade'' is said to feel like it just came out of the forge, and it burns whatever it hits.
* In ''Literature/CodexAlera'' many of the High Lords firecraft their swords, because a bleeding wound can be watercrafted better easily enough, but a cauterised 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.

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[[folder: Real life ]]

* [[http://www.webcitation.org/query?url=http://tribune.com.pk/story/219719/excorcism-16-year-old-tortured-with-hot-knives/&date=2011-07-29 Sufi tortures teen with hot knives]].
* Heated blades have been used for crude amputations to cauterize and disinfect the wound.
* Actually not a good idea in real life, even if it were feasible; as any blacksmith or metalworker can attest, steel loses its hardness the closer it gets to its melting point. It'd take some very special metallurgy for the material to both glow white-hot ''and'' still be viable as a hard cutting edge.

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[[folder: Tabletop Games ]]

* Many Warhammer swords (at least in the way they are visually depicted), both ''WarhammerFantasy'' (Archaon) and ''TabletopGame/{{Warhammer 40000}}'' ('''THE GOD-EMPEROR OF MANKIND'''), even when some flames might flicker depending on the artist, verging into FlamingSword territory.
* ''TabletopGame/MutantChronicles.''
* ''TabletopGame/CallOfCthulhu'' 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.
* ''TabletopGame/{{Exalted}}'': A Malfeas charm turns a blade too burning hot ''[[InvertedTrope 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.
* And of course ''DungeonsAndDragons'' is full of these. As well as (among others) [[ShockAndAwe lightning]] and [[AnIcePerson cold]] versions. Not restricted to bladed weapons, though...

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[[folder: Video Games ]]

* The Heated Cosmic Knife from the Dead Money expansion of ''VideoGame/FalloutNewVegas'' is this. It's an indestructible AbsurdlySharpBlade that has been heated with a heating pad and apparently retains its heat for a ridiculous amount of time, giving it even more destroying power.
** There is also the Saturnite Fist in ''Old World Blues'' dlc. Just give it to the crazy toaster in Big MT and it will become the Saturnite Fist Superheated which glows red hot and sets enemies on fire. A wonder how you [[ConvectionSchmonvection don't burn your own hand]] while wearing it.
** The base game has the Thermic Lance.
* One of the bosses from ''VideoGame/ChronoCross'' uses a {{Steampunk}} version (a NighInvulnerable, HumongousMecha), but this is technically a fantasy setting.
* The (in)famous Pyrotechnic Axes in ''[[ArcanumOfSteamworksAndMagickObscura Arcanum]]'' presumably work this way.
* VideoGame/{{Strider}} Hiryu's Cypher uses plasma to achieve this effect.
* Nero's Red Queen from ''VideoGame/DevilMayCry 4'' 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.
* Though they are not technically swords, the hooks thrown by Spider Splicers in the ''Franchise/{{Bioshock}}'' games are glowing red hot. They are probably heated by plasmid use on the part of the splicers.
* The Thermic Lances in ''VideoGame/{{X-Com}} 2'' are a combination of Hot Blade and {{Vibroweapon}}, and are pretty effective against the [[DemonicSpiders Demonic Crabs]]. [[note]]Ok, they are actually lobsters.[[/note]]
* The [[http://masseffect.wikia.com/wiki/Omni-blade#Omni-Tool_Weapons Omni-blade]] in ''VideoGame/MassEffect3'', the hologram is so the user doesn't accidentally burn themself.
* In ''VideoGame/MetalGearRisingRevengeance'', 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 HotBlade; just an exceptional VibroWeapon. 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
* A variation from ''VideoGame/HalfLife2'': an [[AutomaticCrossbows electromechanical crossbow]] that launches red-hot ''rebar rods''.
* ''VideoGame/{{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.
* In ''VideoGame/SuperRobotWarsCompact2'', the Alt Eisen carries a "Heat Horn" mounted on its head and functions like the Heat Hawk of the Zaku II. When it's [[MidSeasonUpgrade rebuilt and upgraded]] into the Alt Eisen Riese, the weapon is turned into the "Plasma Horn", with an additional feature of ShockAndAwe.

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[[folder: Western Animation ]]

* WesternAnimation/{{SheZow}}'s EvilTwin [=SheZap=] has a curling iron that combines this with LaserBlade.

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