Therefore the Lord God sent him forth from the Garden of Eden. He drove out the man; and He placed at the east of the Garden of Eden Cherubim, and a flaming sword which turned every way, to keep the way of the tree of life.
Shishio in Rurouni Kenshin. It's a particularly nasty one, too. Instead of using magic or a napalm-like substance, Shishio's sword burns because, after using it to kill countless people, the blade's serrations have become filled with human fat. One spark from a clash of swords, and all the fats and oils the sword's soaked up go into a blaze.
Hiei in YuYu Hakusho occasionally uses the Sword of the Darkness Flame. Kuwabara's Rei-ken is a combination between this and a Laser Blade, since it's made of his own ki.
Signum's Laevatein in Magical Girl Lyrical Nanoha is both this and a Whip Sword. Bonus points for being named after the mythical Norse sword that will bring about the end of the world, and for Signum (a.k.a. "Blazing General") bearing resemblance to Archangel Michael (a.k.a. "Strategos of the Heavenly Host").
Captain Yamamoto, besides being on fire himself when fighting, has a flaming sword. Bearing in mind that he can drive people to the ground with a glance, it's no surprise that his sword puts off enough heat to burn the clouds out of the sky. His Bankai trades in the fire for all the heat of his flames being concentrated along the edge of his blade. The heat is so intense that just by touching the ground with the sword's tip, he atomizes the ground in the direction he was cutting.
The Filler villain Shusuke Amagai takes this up to eleven with his bankai. It's basically a BFS with an afterburner for a hilt.
Isshin Kurosaki's Shikai is surrounded by flaming reiatsu.
Zoro once had all three of his swords on fire during a firestorm, and used them to great effect during the Little Garden Arc. Also, he can apparently light his swords on fire with the force of his swing, which he used to defeat Ryuuma. May also qualify as a Desperation Attack.
Hannyabal uses a flaming naginata called Kessui.
Fossa of Whitebeard's Commanders is able to set his sword on fire, by lighting it with his cigar.
Kin'emon has an entire fighting style revolved around this, to an extent.
Madoka Mawari has two in Tenjho Tenge. She also burns her skirt off to give herself higher mobility while using them.
Dai, the eponymous hero from Dai no Daibouken has used fire magic on some occasions to turn any sword he wields into a Flaming Sword. But this isn't limited to fire spells, as he can also combine his sword with lightning magic for an even stronger power-up.
Naruto Susano'o, the spirit warrior projected by the wielder of the Mangekyo Sharingan, uses the Totsuka no Tsurugi; a spirit blade looking like nothing so much as a long flame, although it stabs through and sprays blood out of Orochimaru quite well. (In the manga it looked less like fire and more like a liquid which, going by the description in the databook, is actually sake of all thing. Cue Fridge Brilliance: Orochi from Shinto mythology was slain after drinking too much sake.)
Berserk: Isidro's Salamander Dagger can unleash a burning power, hot enough to melt steel. Also, during the battle in the city between Guts' party, the sea monsters, Daiba and Ganishka, Schierke uses her fire magic to turn the Dragon Slayer into one of these.
Stiyl Magnus and his fire demon Innocentius both wield swords of solid flames.
Fiamma of the Right's flaming sword also doubles as a BFS that's forty kilometers long.
A minor antagonist named Richard Brave wields Lævateinn, a flaming sword of his own creation that uses a combination of magic and science to work. Unfortunately, creating this weapon caused the Magic Side to condemn him as The Heretic for violating the laws separating Science and Magic. Richard swore revenge for this injustice and for the Magic Side dissing his awesome creation.
In Fairy Tail, Natsu briefly wielded a sword like this that helped him break out of Tartarus' prison. He lost it when he attacked Black Mage Zeref with it. The sword's blade was broken off while his target was completely unharmed.
In The DCU, the Jean-Paul Valley incarnation as Azrael not only wields a flaming sword, he can shoot several of them. Azraels throughout history have wielded a flaming sword in their guise as angels. The Knightfall novelization lovingly details how the sword has advanced through the centuries, from a sword wrapped in soaked rags and set on fire just before Azrael's appearance, to its then-current twin hollow gauntlet-mounted daggers with compressed air propelled through them to fuel the fire.
In the comic book Angel: After the Fall, Angel wields a fire sword against the champions of the lords of Hell-A.
The Roman God of War saw the efforts of the Germans in WWII, and was impressed. He decided to help them, but because he was an idiot he accidentally gave powers to Clay Carter, American. The powers include super strength, agility, invulnerability and The Flaming Sword Of Mars, which is... a flaming sword that can cut through anything. He becomes Man Of War, a Golden AgePublic Domain superhero.
Rustam, a recurring enemy of the Suicide Squad through his involvement with the terrorist group Jihad, wielded a "psi-scimitar", with a blade of fire erupting from its hilt. In their final confrontation, Rick Flagg manages to kill him with it.
Lourdes, the leader of Pax Galactica, wields a magical flaming sword that burns even in the vacuum of space. Superman borrows her weapon and uses it to slay a Planet Eater.
Johnny Storm (the Human Torch, a guy who is a master of flame in all its forms and can't be burned by them) of the Fantastic Four had the bad luck of running into Hellfire and an archangel's flaming sword in the same story arc. The hellfire burned him badly, but the archangel's sword hurt even more.
Darkseid's created fire giant Brimstone creates a sword out of literal flame to deal with "Justice League Detroit" in Legends.
In How to Train Your Dragon 2, Hiccup wields a retractable sword coated in Monstrous Nightmare spit, with a mechanism to ignite it when needed. The sword's hilt can spray flammable Zippleback gas, which Hiccup can then ignite with his sword.
Violet, the protagonist of Ultraviolet, and her arch-nemesis, have a flaming sword duel after she renders his flame-throwing pistol useless.
The Headless Horseman from Tim Burton's Sleepy Hollow wielded a variant. While it didn't appear to be burning, it was so hot from the eternal flames of Hell that it still cauterized any wounds inflicted.
The High Priest of the Mayan temple in The Fountain wields a flaming sword with which to defend the Tree of Life. It's actually a bit of Deconstruction, as the Mayan priest basically distracts Tomas with the sword and stabs him in the gut with a dagger.
In Pirates of the Caribbean: Dead Man's Chest, Will Turner lights his sword on fire by dipping it in oil then smashing a lantern, in an attempt to intimidate and fend off a number of Davy Jones' crew. Note that he never actually fights anyone with his flaming sword. This is because the prop for this scene was actually quite dangerous as it was basically a tube through which flammable liquid was pumped to fuel the fire.
Yor: Yor briefly fights with a sword that is on fire.
The Sommerswerd has holy sunfire on its edge when it faces particularly evil foes. This property is on display in the videogame spin off.
The Darklord blades, like Helshezag or the Dagger of Vashna, are surrounded by black flames when used.
If Lone Wolf has reached the rank of Sun Lord or higher and has Grand Weaponmastery, he can turn an ordinary sword into a Flaming Sword. Not nearly as powerful as the Sommerswerd, but useful in places where drawing the Sword of the Sun will get you killed.
Flaming swords are the favored weapons of Nadziranim under the ice dragon form.
In the Fighting Fantasy title Island of the Lizard King, swords like this are the only thing that can harm the Lizard King; and he uses them himself, oddly enough, keeping them in his fortress.
The sword of Discworld's Chaos is made of blue fire, a flame so hot that it goes to the other side and becomes absolute cold. On his off days, he uses it to keep the milk he sells fresh. Also, in Lords and Ladies magic is described as being like "a flaming sword that burns all the way down to the pommel" to emphasise how dangerous using it is, and why wizards and witches don't use it for mundane things.
The Midnight Angel from the Wild Cards series is able to summon a gigantic flaming sword as one of her powers.
In A Song of Ice and Fire, flaming swords are a religious aspect of the religion of R'Hllor. Their messianic figure wielded a flaming sword called Lightbringer. Several followers of R'Hllor also wield flaming swords of various authenticity.
Thoros of Myr wields a flaming sword in melees and battles, but it's just a trick. He buys a cheap sword beforehand and douses it in flammable wildfire to intimidate his opponents and spook their horses. It's said to also ruin the sword in the process.
Stannis Baratheon acquires a flaming sword he calls Lightbringer. Upon closer inspection it's a magical trick. The flames shed light, but not heat. The flames of the legendary Lightbringer would burn.
Beric Dondarrion wields a flaming sword when he duels Sandor Clegane. After cutting his palm on the blade, fire bursts from the blood. Unlike the other swords, the flames really burn, which is bad for the pyrophobic Sandor. However it's mentioned earlier that setting your sword on fire makes the steel brittle, and Sandor wins because the sword breaks when Dondarrion is about to make the killing bow.
Though ironically the protagonist of The Blade of the Flame doesn't use a flaming sword, his half-orc partner Ghaji gets a flaming axe during their infiltration of Dreadhold. They have to use it up to defeat the dire wereshark invasion in the climax of the series, however.
In Good Omens, Aziraphale, Angel of the Eastern Gate, has one. He ends up giving it to Adam and Eve to help them survive after they are cast out of the garden of Eden. God's reaction goes as thus:note At the end of the book it is strongly implied that this becomes the Sword of War; Aziraphale picks it up and gets it to light up again.
"25. And the Lord spake unto the Angel that guarded the eastern gate, saying Where is the flaming sword which was given unto thee?
"26. And the Angel said, I had it here only a moment ago, I must have put it down some where, forget my own head next.
"27. And the Lord did not ask him again.
Subverted rather neatly in Harry Turtledove's Wisdom of the Fox. The protagonist, amateur wizard Gerin the Fox, discovers an ancient book with a section titled "A cantrip which produceth a flaming sword." Gerin proceeds to hang a lampshade on Ye Olde Butcherede Englishe. Then he tries the spell. It works; his sword bursts out in pure, smokeless elemental fire. Then he discovers the problem with the spell that explains why not everyone uses it. The spell covers your sword blade in fire... but gives you no insulation or protection from the heat created by the fire. Luckily for him, he manages to drop the sword in a barrel of water before his hand gets blistered too badly.
Late in Brisingr, Eragon gets the titular sword. Whenever he says its name (which means fire in the ancient language), it ignites. One character at least has the sense to point out this is incredibly cheesy. He finds out by saying the name of the sword and then dropping it in surprise—definite Crowning Moment of Funny. Flametongue swords in Dungeons & Dragons do the same thing.
The Balrogs in J. R. R. Tolkien's Middle-Earth mythos (The Lord of the Rings and The Silmarillion) wielded not only a flaming sword, but also a flaming cat-of-nine-tails whip. Well, the one in The Lord Of The Rings used a flaming sword at least. Gothmog (the leader of the Balrogs) used a flaming axe, the weapons of the other Balrogs are not known, but were presumably flaming as well. Also, while Andúril is not literally on fire, it does shine "as though on fire." Even more, Túrin son of Húrin has his own blade, which after a very Kamina-esque speech, he thrusts in the air and a great fire leaps up all around him. One of Gurren Lagann's writers just has to have read that for Kamina. At one point Andúril did burst into actual flame, courtesy of Gandalf the White. Also, the Witch-King's sword has red flames during his encounter with Gandalf, just as depicted in the extended movie version.
Dyrnwyn in the Chronicles of Prydain. This is the same sword that is one of the 13 hallows, or treasures, or Britain.
In Codex Alera, any sufficiently skilled firecrafter can light their sword on fire; however, it takes quite a lot of power to be able to do so, and as such is a technique mainly used by the immensely powerful High Lords. Being struck with one of these is what killed High Lord Aquitaine; were it a normal wound, he could have simply watercrafted it shut, but a flaming sword's wounds cauterize themselves, making healing impossible. They're also favored for anchoring firecraftings.
In Farworld: Land Keep, there is a type of sword called a Flazite, made of dark metal with flames "leaping about on the surface" despite the rain. It gets worse- one scratch, and your blood turns to fire. And...it's pointed at our heroes. Crap.
Kröd Mändoon and the Flaming Sword of Fire. Yes, that is the show's name, and yes that is the title character's weapon. However, being a parody and all, Krod has no control over the flaming part. It tends to catch fire when he's "excited". Hell, the first time someone asks about it, Krod says he thinks the sword is somehow defective and he needs to get it fixed.
In the Fallen mini-series, angels and Nephilim can wield swords made of pure divine fire, which they can summon from thin air. Being hit by one usually incinerates the target. Strangely enough, the protagonist, a regular kid until recently, can match his swordfighting skills with angels, who have been doing this since before humans were around, and even The Devil.
Kaamelott has Excalibur, but fortunately it extinguishes itself whenever Arthur puts it down. As he discovers later, it only catches on fire when held by a person of incredible destiny, to his swordmaster's chagrin and Perceval's surprise.
Game of Thrones: flaming swords have religious significance in the religion of R'hllor, the Lord of Light.
Stannis is introduced during a religious ritual to R'hllor in which he pulls a flaming sword from a burning idol. The sword is supposed to represent Lightbringer, a flaming sword of legend, but it quickly gutters out.
Beric Dondarrion causes his sword to magically burst into flame and uses it to fight a trial by combat with Sandor Clegane, who is pyrophobic.
Ultraman: Ultraman was on the receiving end of one of these when he fought an extremely formidable monster called Firemon. The sword was so hot it badly burned him even with a light slash. Then Firemon put it Up to Eleven by doing a hot knife through butter impression and impaling Ultraman with it. This was more than enough to kill Ultraman and he needed a resurrection in order to have a round 2 with Firemon. Ultraman repays the favour once Firemon is disarmed and throws the sword right through Firemon's head for the victory.
Surtr, the leader of the giants of Muspelheim had one (called "Lævateinn"); his having it plays a major role in Ragnarok. It will burn nearly all of the earth. Oddly enough, he gets stopped by a tree of all things (granted, it wasYggdrasil).
Lævateinn itself was forged by Volundr and owned by Loki. The Old Norse translation literally means "Damage Twig" and may in fact not be a named sword, but a kenning for a sword.
One of the 13 treasures of Britain, The Dyrnwyn of Rhydderch Hael, is a sword that would light up on fire that does not harm the wielder if drawn by a noble man.
Commonplace in Garbage Wrestling (and sometimes makes its way to the professional world), it's entirely possible to see things set aflame to look more intense and painful, including but not limited to tables, two-by-fours wrapped in barbed wire, and the wrestlers themselves.
This is the major schtick of the Bright Wizard in Warhammer, though other wizards have similar weapons and Daemons can crack out the flaming blades on occasion as well. Also, one of the spells available to the Bright Wizard is called Flaming Sword of Rhuin casting it on a friendly unit provides the entire unit with a buff that lights their weapons on fire.
One of the examples of common relics in the In Nomine core rules is a flame sword.
The Flaming Weapon spell from GURPS: Magic. A naturally flaming sword requires a valuable ruby to be placed on the hilt.
Zero gets many techniques that use these in the Mega Man X and Zero series. Most of these attacks are executed in a manner similar to the Shoryuken.
The weapon of Sword Man (which Mega Man can acquire) in Mega Man 8 is called the Flame Sword. Or "Flame Suword".
Throughout the Mega Man Battle Network series, Swordy Two enemies have flaming swords and Swordy Three enemies have ice swords. You, of course, also have fire and ice swords once you've beaten them. In the third game, along with the fire and ice swords, there are also swords made of electricity and bamboo. There is even a Program Advance in that game that allows you to smack your enemies with all four swords in just one and a half seconds for massive elemental damage.
Phantasy Star Universe has the Crimson, an S-rank saber that glows red and is constantly on fire. There's also a Twin Saber version called the "Two-Headed Ragnus." Unfortunately, while they look badass, their damage output isn't that great compared to other S-ranks in the same category.
Final Fantasy games often have elemental weapons of this variety, or the means to apply the effect to your existing weapons, conveniently for sale at your local store. Or at least in some treasure chest somewhere. The Mystic Knight/Sorcerer job in V is just for doing this. Vivi and Steiner collaborate in IX. Final Fantasy XI has such effects as native abilities for Red Mages and Summoners, as well as some weapons possessing some lesser effects. The Flame Saber, Ice Brand, and Coral Swords (each representing part of the Fire, Ice, Lightning triumvirate, respectively, have been available since the earliest games.
Dragon Quest has these as a staple, and will typically cast a fire spell when used as an item.
In The Legend of Zelda: Phantom Hourglass, if you return 10 Power Gems to the spring at Spirit Island, and equip the Fairy of Power, Link's sword becomes coated in flames. Ten more and they burn hotter and the tip is literally aflame. Spirit Tracks gives these kinds of swords to Torch Phantoms so as to act as a light source; beyond that, there's nothing else different about them.
Kain can get one of these fairly early on. It's extremely powerful, but has the disadvantage of burning your opponents to ashes, thus leaving nothing to feed on - remember, Kain is a vampire.
There's also the Fire Reaver that Raziel can get in all three of the games he's in.
Later in the series, it's revealed that the Hylden champion is supposed to wield a flaming sword. Raziel takes this to mean that he is the Hylden champion, because the Wraith Blade quite resembles a flaming sword.
Diablo II featured the Archangel Tyrael, who used a sword that burned with holy flames, before Baal wrestles it away.
The sorceress can also enchant weapons with fire. Of course, this ability is almost completely useless in solo play, due to their Squishy Wizard status. But with the right gear and Minmaxing, they can dish out 100k+ damage per hit turning them somewhat into Glass Cannons dealing more damage than just about anything else in the game.
In Neverwinter Nights, the player can apply alchemical fire to a sword to make it burn and deal fire damage. You can also apply visual effects to swords with the toolset, which include (in addition to flaming) glowing yellow-white with holy power, dripping acid, crackling with electricity, giving off visible sound waves, generating a miniature blizzard, and glowing red with unholy power. The actual effects that the appearance would create require manipulating the weapon's properties too, though.
Enchanting weapons with elemental properties has been a staple of World of Mana. In Seiken Densetsu 3, Duran's dark-aligned classes all specialize in such magic, as does Carlie's light-aligned classes. Two of Kevin's classes possess similar spells, which don't enhance a weapon's damage with an element, but instead add HP or MP draining effects.
In the doujin fighting game Eternal Fighter Zero, Mishio Amano's fighting style involves enchanting her spear with fire or lightning to access different movesets.
Elemental effects are a large part of the Guilty Gear games. Sol Badguy actually wields a sword that has no sharp edge or point but is a great vessel for his fire magic, and French cop Ky Kiske has a regular sword charged with lightning magic.
In The Elder Scrolls: Tribunal, the player must reconstruct True Flame, a flaming ancient sword capable of killing gods. However, the means to create it have become Lost Technology since the original was forged, so the player descends into the ancient ruins to find the ghost of the dwarf who originally made it. The flaming component turns out to be a rare tar that burns eternally when set alight. When you bring him the pieces of the sword and the tar, he mutters something to the effect of "kids these days, a sword that can cut through bone like butter isn't good enough, now it has to be flaming too." You can also enchant your own flaming swords, and a couple come up in the games themselves. The Sword of the Crusader, in the Knights of the Nine expansion to Oblivion, may be the most prominent. Like the sword in Tribunal, you first need to recover it as an ordinary sword, and in this case reconsecrate it to the gods before it will light on fire for you.
You can snag one of these pretty early in Ultima IX. As with all good flaming swords, it doubles as a handy torch in the dark.
NetHack has a couple which seem to fit the bill; Fire Brand (which is actually pretty rubbish - it's cold counterpart, Frost Brand, is far more useful) and Sunsword (which is more for dealing with undead, but at least it doubles as a torch).
Not only is there a Flaming Sword, but an Ice Sword, an Earth Sword, a Water Sword, and an Illusory Sword as well, there is even a Flaming Axe; each allowing the wielder to channel certain types of magic.
A Cosmic Keystone in the game is also one and can shift into 3 different types and helps channel magic as well.
In Castlevania, some of the entries have flaming swords, whether it's the Firebrand or the Flamberge, or something else entirely. In particular, Castlevania: Symphony of the Night has a pair of flaming swords, the Firebrand and Marsil. Not only do both swords have a fire aura, but with a command input both can generate a wave of flame, with Marsil's long enough to hit something a 1/5 of the screen away.
Fallout 3's Shishkebab is one of these. The ingredients? Lawn mower blade for the blade itself, motorcycle gas tank for the fuel storage, motorcycle handbreak for the handle/trigger, and pilot light to ignite it. With the right perks, it is one of the best melee weapons in the game, and flat-out the most powerful in the pre-expansion game. It returns for Fallout: New Vegas, complete with a unique variant made available with the Gun Runner's Arsenal DLC. It's still pretty good, though not quite as much as it was in Fallout 3.
No More Heroes has Bad Girl, who wields a flaming baseball bat, made possible by her spitting alcohol all over it and lighting it up.
Any melee weapon with a Flame Augmentation in Fable will do this from time to time. Heck, you can put a Flame Augmentation on a frying pan. It also happens in Fate, where you can even double up on enhancements, creating a Flaming Sword of Fire. Weapons with Fire as a property can also have Frost, Lightning and/or Holy enhancements.
Kratos uses one of these in Tales of Symphonia. Near the end of the game, he gives it to his son, Lloyd.
In Devil May Cry, Dante fights with flaming gauntlets. In DMC3, he uses a flaming sword called Agni, earlier wielded by a boss and also fights demons with flaming scythes. Nero's Red Queen has Exceed system, which briefly sets is on fire during attacks.
World of Warcraft - You can have an enchanter put a spell on your melee weapons, which some of these give your weapon a certain glow, whether it be on fire, blue for an icy death, or even green.
Kazuki in Samurai Shodown wields a flaming sword. The series goes further in Samurai Shodown V when a demon who looks basically like Kazuki wields Chains of Fire instead. Samurai Shodown 2 has the Weapons Kitchen Sink: Neinhalt Sieger has a flame-enhanced huge gauntlet (which also helps him with his flaming leap), and Wan-Fu uses a flaming stone pillar.
Beyond Oasis brought us the Omega Sword. It's not clear if the sword itself is on fire, but it certainly lights up enemies as if they were. Going through the Bonus Dungeon gave the player access to one that would never break.
In Nexus Clash, the Holy Champion class can learn the Cloak of Flame skill. It turns the character into living fire, giving them a flaming sword, the ability to throw fireballs, a "rain of fire" area attack, and a burning aura.
In Eternal Sonata, any BFS in Jazz's hands can be used in the special attack Heat Blade. "The fire on the blade burns all."
There is one of these in Battle for Wesnoth's original campaign, Heir to the Throne, in the Snow Plains scenario.
The Flameberge (not a typo) in Scribblenauts. Typing in "Flaming Sword" works just as well though.
The Crisis Core version of Odin has his Zantetsuken start as one of these, get the flame extinguished, then have it rekindle before landing the killing blow.
In Lost Odyssey, wearing a fire-elemental ring gives you one of these (or a flaming staff, or what have you.) There are also air, earth and water variants for their respective rings.
Warcraft 3's Doom Guards (think Balrog without whips and not on fire) have them. Orc Blademasters don't use them, but they do come from the Burning Blade clan... unless they have an Orb of Fire, which orbits the hero's weapon and allows him to throw fireballs.
In Persona 3, it's possible to obtain Surt's flaming sword as a weapon for the main character and Junpei.
Just Breed has a truly nasty one, overlapping with Fire-Breathing Weapon — it's just called a generic 'flame sword', but every time you attack with it, it hits nearly half the battlefield with an absurdly massive area-effect cone of fire.
The Seven Strike in Ōkami looks like it's on fire, as well as being red and orange. Despite this, it's not actually on fire - the effect is merely its prongs moving. The actual fire weapon isn't a blade.
This is a common weapon in the Ys series. In most games, it's either the Infinity+1 Sword or close to it.
In Rastan, the Fire Sword was the strongest of the weapons the title character could obtain, and would shoot fireballs when swung. Rastan Saga II turned the flames into an add-on power-up instead of a weapon in itself.
There are many of Sagi's fire element weapon magnus in Baten Kaitos Origins. When any fire-weapon is equipped, Sagi's held weapon leaves a red-orange trail behind it, and the blade appears to burn.
In Dragon Age: Origins, flaming blades can created via enchanted lyrium runes or the Flaming Weapons spell, maintained by one of the Mages in the party. The Templars also have flaming swords depicted on their armour, symbolising the Sword of Mercy that provided the Mercy Kill to the Prophet Andraste when she was put to the flame. Their actual weapons however are normal steel, presumably because their Anti-Magic abilities render enchanted blades useless, since any magical flames would be quickly snuffed out.
One of the divine powers available in Age of Mythology is named "Flaming Weapons". It allows your soldiers to do extra damage for a considerable time, particularly against buildings.
In Disgaea 4, the Dragon's Flame Slash magichange attack has the dragon turned sword ignite itself before its wielder strikes the target, who proceeds to catch on fire, then explode.
In Psychonauts, Oleander's dad gets flaming meat cleavers the second time you fight him.
Sa Ga Frontier 2: The Firebrand, Finney Kingdom's sacred treasure. Any potential king of Finney undergoes a Rite of Passage where they hold it up in the air and, if it generates flames, proves their worth as a ruler. But for Gustave XIII, nothing happens.
One is used by Gwyn, Lord of Cinder. If you use his soul in a weapon ascension, you can make a non-flaming version. You can set your own sword on fire by using a Charcoal Pine Resin.
Inversions include Dragon upgrades from Demons Souls and Fire/Chaos upgrades in Dark Souls gives your weapons fire damage, but the weapon itself doesn't burn. Played straight with Queelag's Furysword, which does burst into flames with every swing. This also holds true for the version used by the Boss as well.
Played straight with the Smelter Demon Sword in Dark Souls II. It's a huge sword-shaped piece of volcanic rock with veins of lava that unleashes flame with each strong atack.
In Drakan, one of the pickup weapons Rynn can use is this. Not only does it set its victims on fire when it hits, it even doubles as a torch for illuminating dark places. As a bonus, the first one Rynn gets to pick up has an alternate attack that creates an expanding ring of fire that burns everything around her. Unlike most swords of this type, the one in this game is not so durable.
In Athena, Athena's most powerful melee weapon is the Flame Sword, which has enormous range and power. Unfortunately, it hurts to swing it.
The fiery greatsword in Terraria is one of the most powerful non-hardmode weapons. The console-exclusive Infinity+1 Sword Tizona also emits flames when swung, although it doesn't look like it's on fire by default. The reason for the flames is in the name: Tizón translates to "burning stick" or "firebrand".
Axe Cop's Fire Slicer has a magic (non-burning) sword that changes to a burning stick as it cuts the enemy.
Knights Of Buena Vista plays with this. Mary tells the guards to set a bunch of swords on fire so that they look like fire elemental weapons, so that they can drive off some frost giants.
In New Vindicators, the original superhumans, Nephilim (Half-Human Hybrids and the children of Fallen Seraphim) have a variety of powers based around manipulating Hellfire, but they can all conjure a weapon made of the stuff, one that can either be solid, but not burning, or psionic, and cut through any armor to harm the soul itself. A lot of these weapons take the form of various swords.
Phoenixfire, a student at Whateley Academy in the Whateley Universe, can manifest fire all over herself and also manifest a sword that is made of fire. Her mom the superhero (Magma) can do the exact same thing.
Yahtzee commented that the shuriken-and-lightning gun in Painkiller "could only be more awesome if it had tits and was on fire."
Dr. Clef's proposal for SCP-001 from the SCP Foundation is apparently the guardian of Eden, complete with one of these that can strike in multiple directions at once, regardless of distance.
In Static Shock, pyrokinetic metahuman villain Hot Streak attempted to use such a weapon, but was defeated before it got to see any action.
The Dinobots in Transformers Animated all have flaming weapons. Grimlock has the traditional sword, but Snarl has a flaming club, and Swoop has a flaming flail.
Zuko and Azula of Avatar: The Last Airbender have used flame daggers and whips, among other things, to engage their opponents. Be aware however that they weren't daggers or whips set ablaze, but actual daggers and whips made of fire. That's like threedifferent aspects of the Rule of Cool combined into one. Zuko also combined Firebending with his swords in his day in the limelight.
In The Legend of Korra, Ghazan uses friction generated by earthbending to make a superheated buzzsaw.
In Codename: Kids Next Door, the Delightful Children From Down the Lane take this trope to the next level by using a giant mech sporting a pair of giant flaming chainsaws.
The Sword of Plundarr from ThunderCats, a magical double-bladed flame scimitar. Apparently when Jaga threw the Sword into a volcano to get rid of it, this somehow led to a chain reaction that destroyed Thundera. Nice Job Blowing Up the Planet, Jaga the "Wise". He didn't even succeed in destroying the bloody thing, and Mumm-ra gets hold of it later on.
Drew, the mom on The Secret Saturdays, wields a sword with actual sculpted-metal flames molded near its tip. It isn't actually flaming, but rather draws power from sunlight. It can, however, become superheated and shoot flame from the tip.