When Armor Is Useless, it makes sense not to wear any. But why stop there? Why wear anything into battle? Anyone can be tough in Powered Armor, but it takes either a really badass hero or a really depraved villain to fight in the nude.
The motivation for this tends to be different for heroes and villains. For villains, it's usually done for creepiness; instead of being silly or titillating it comes off as really, really scary. The nudity emphasizes brutality and aggression instead of being sexy. It can also indicate that the villain doesn't care at all what people think about him. He left normal human motivations, like modesty and shame, behind him, or maybe he has an Übermensch-complex. Or, very creepy indeed, that bloodshed turns him on.
Naked heroes generally don't really have a motivation because they generally don't choose to do it; when a good guy fights in the nude it's usually out of necessity, from their clothes being stolen or destroyed. This is why a naked hero tends to come off as badass, while a naked villain usually comes off as insane.
For both alignments, nakedness can be associated with innocence and nature. The hero may be one with nature, while the villain isn't really human, more like a predatory animal or a natural disaster, see the fifth variant of True Neutral.
Another part is that it seems reckless to go naked in the face of carnage or combat. It implies that the character is so powerful he doesn't need armor, or he just doesn't care about defence.
The Logical Extreme of Walking Shirtless Scene. See also Evil Is Sexy for villains who wear just enough...
Not to be confused with military frontal assault, or anything of the kind done by Neo Zeon forces. Also not to be confused with Informed Equipment, the trope formerly known as Fight In The Nude.
Oh, and a side note. When someone does this, its a good sign that they might be a Shameless Fanservice Girl.
Has nothing to do with the Char Clone of the same name, nor does it show up in the Ratchet and Clank game titled as such.
open/close all folders
Anime & Manga
A Certain Magical Index: Right in the 1st episode, Index challenges Touma to use his Imagine Breaker, since she didn't believe in its powers (just as he doesn't believe in her magic). He uses it on her "Walking Church" (A magic priests robe to shield her from danger). Since the magic that sustained her robe was nullified, the robe goes into shreds and Touma gets an eyeful of her loli physique... And is bitten in revenge.
Once pictured above: Lucy from Elfen Lied, who, after having escaped from an underground vault where she was kept in a full body straitjacket chained to a steel cage, spends her first scene wearing nothing but a helmet, killing people left and right very messily.
Greece references this a lot to Japan, and one can assume he has done it.
Incognito. We never see him with even a stitch of clothing on, and most of the time he is fighting or planning to fight Alucard. Granted, he barely looks like a human and has no genitalia...
Alucard technically counts as well considering that his clothes aren't really clothes, just another part of his body.
Knives does this a few times in Trigun and Trigun Maximum. Made even more disturbing by the connotations of twincesty rape at the end of the Trigun manga.
Mistress Centipede from InuYasha, whose bottom half is a massive centipede, but whose top half is a very naked human woman. Also, Naraku. However, Naraku is only shown undressed when the lower portion of his body is covered in demons, he usually wears a pelt or robe of some kind, particularly with his newer form.
In Saint Seiya, Seiya attacks Gemini Saga, which only destroys the Pope robe he's wearing; Saga ends up naked, in the shadows. Yeah, he dons his armor a few seconds after, but seeing him naked in the shadows during these seconds is pretty intimidating. In the OVA Seiya himself does this, to Apollo nontheless.
A voluntary heroic example in Madlax. In episode 16, the title Action Girl throws her white dress away and then attacks the goons out to get her and Vanessa.
Paio II is perfectly willing to Flash Step out of her clothes and use them as a Ninja Log so she can attack her opponent from behind. She comments that being willing to do a full frontal assault increases her potential as a fighter.
That actually happened "earlier" (sorta), in the first Girlfriend of Steel game, during a brief attack on Tokyo 3. Shinji was staring through his window and Asuka was taking a shower; she had no idea that Shinji was at home so she ran outta the bathroom in the buff to see what was going on, but the enemy left extremely fast and she had no time to retrieve her clothes or a towel. Asuka then realised Shinji was at home and right behind her and kicks him in the face.
Heroic example: Gray from Fairy Tail is pretty prone to these. Even while in the Guild he can suddenly and inexplicably end up naked, and it always surprises him. It is revealed that is a result from his teacher's training, she made him and Leon train naked in the snow so Gray strips off when he's not paying attention. Later on it doubles as a Let's Get Dangerous when the pair do synchronized stripping when fighting tough opponents.
Voluntary heroic example: Kekko Kamen. Fight crime while wearing boots, gloves and a mask... and nothing else.
Gyoubu from Basilisk not only strangles people to death in the nude, he spends most of his screen time like that. His ninja ability allows him to fuse with his surroundings as long as he is naked.
In the final arc of the original manga of Riki Oh, the first confrontation between Riki and Mukai involves the latter completely naked...and completely dispassionate. The (accurate) impression is that Mukai has no interest in acceding to human desires and/or expectations. Since he also sleeps that way (and no, he didn't have any company), the point is pretty obviously that when Riki came calling, he didn't adjust any part of his routine for him.
In Claymore the awakened beings fight naked, justified because their monstrous forms are too large or inhumanly-shaped for human clothes. Examples of this happening when they are "human" include...
Riful is explicitly shown stripping before action so as not to ruin her clothes. Her lover Dauf apparently does this as well.
Agatha appears as a naked woman connected to a giant monster by her hair. Although technically the naked woman part isn't her real body.
The "Abyss Feeders" are monstrous yoma shaped into a human form. They appear as mindless, almost-naked women with their mouths and eyes sewn shut and possess ridiculous regeneration abilities. They can usually heal damage to their bodies as fast as their opponents can inflict it and only a well-aimed blow to the head can kill them outright. Since their scant clothes cannot regenerate, when fighting they will inevitably end up completely stark naked given enough time.
Priscilla also does this when fighting in awakened form note in which it can be excused since despite being humanoid she is just too big for the clothes she wears in human form and quite often in her human form too note where it can either be the result of her clothes being destroyed or else the result of her complete lack of understanding why she should wear anything.
Shigure encountered a few assassins in the hotspring during the trip with Kenichi.
Later, Shigure is captured by the organization Yami and she is stripped naked, a reasonable precaution since she can turn anything, even a piece of cloth, into a deadly weapon. She manages to get needles into her mouth and break her restraints. Though her escape attempt fails, she kicks a lot of ass in the process.
Major Motoko Kusanagi of Ghost in the Shell does this because of necessity — her cyborg body's invisibility does not affect clothes, which is quite logical for a Sci-Fi series.
Batou is always there to hand her a coat when she's done kicking ass, though.
While it does look the part, she is not naked. She wears a VERY skintight, thin thermo optical camosuit, that can only be seen by the neckline (it's more pale then her skin), and has to be accompanied by a headpiece with the same capabilities. You cannot see her nipples with this suit on, where indeed you can in the opening. Not that you would expect to see much of that anyway.
Kei, the local Action Girl in Getter Robo: Armaggedon, pulls this right after an Out-of-Clothes Experience in which she finds the equally naked Go. Who actually is her older brother. Sortof.. After this incident, she hops into her mecha in the buff and immediately attacks the enemy, curbstomping all of them.
In Busou Renkin Genji Ikusabe's kakugane ability gives him a near-instant Healing Factor as long as he's holding onto his spear. At one point during his fight with Papillion, his entire body is destroyed (along with his clothing,) leading to him regenerating and spending the rest of the fight stark naked.
Heroic example in the Tengen Toppa Gurren Lagann movie: Lordgenome, the former Big Bad, fights the final enemy naked while in his mech — thankfully, he has a flame of Spiral energy censoring his weiner. Justified, as he was an Oracular Head who recently had his body recreated.
Earlier, in the Hot Springs Episode, the main characters are enjoying a hot sauna bath when suddenly the whole facility turns out to be an enemy mech in disguise; intended to lure them in and catch the off-guard. Most of the rest of the episode then consists of the team fighting ninja / bunny girls and robots while buff naked. In most scenes, only a few, very obvious, Scenery Censor placements kept the naughty bits out of view. When Viral arrives moments later to duel Kamina, he breaks off his intro speech in order to tell them to Please Put Some Clothes On.
Even before this, in Dragonball, Goku was fully prepared to fight an opponent naked after all of his clothes were destroyed by his Oozaru transformation. Luckily, Krillin was there to convince him to borrow his uniform before resuming the match.
Alien anatomy aside, once Frieza reaches his 4th form he plays this trope straight. Oddly, nobody comments on it, though it may have been because they were terrified by his sudden switch from Axe Crazy to Tranquil Fury.
This goes all the way back to the first episode, where Goku goes fishing naked so he doesn't get his gi wet. When a giant fish attempts to eat him instead, he kicks it around clad in nothing but his wristbands.
Episode 4 of the Patlabor OAV series had a scene where most of the SV2 members were in a communal bath, when the water on the men's side suddenly turned red. Everyone on that side screamed, to which Kanuka Clancy responded by jumping out of the bath, running over to the men's side, and pointing a gun through the doorway. (Yes, she had a gun with her even when in the bath.) Noa Izumi is the one to tell her to please put a towel on.
A hentai OVA called F-Force, featured the hero and his female fighters finishing the Big Bad off completely naked. No Barbie Doll Anatomy, naturally.
Detective Conan sometimes has a case where the murderer has no evidence on their clothes due to having killed naked. One case's main evidence of the murderer was a picture of a mole on the collar bone... but no suspect had such a mole. Turns out the murderer killed naked and the 'mole' was actually a blood drop.
In the Bleach Bount filler arc, Yoruichi briefly fights off a Bount like this when she changes from her cat form into her human form. She never does this in canon, but given her legendary lack of shame, she probably would.
Dark Schneider, the lead character of Bastard!!, does this frequently.
Suigetsu from Naruto is introduced this way since his main ability is to turn into water and a full body transformation doesn't always include his clothing when he changes back.
In the original (unedited) version of Yu-Gi-Oh!, there are a few female monsters that are naked when summoned with the Solid Vision System, covering themselves with their hair (including Water Omotics and Dreamsprite). The dub version covers them with swimsuits.
Sorta used in Digimon Tamers. When Takato, Jenrya, Ruki and later Ryo merge with their digimons, their clothes pretty much disappear and they're seen naked "within their Mons". Most likely symbolic, however.
Kakugo the main character of Apocalypse Zero can't remain clothed, and will even strip naked to battle most of the enemies of the series.
In one episode of the Tokko anime, Kureha is attacked by phantoms while taking shower, leading to a fight scene where she's slicing through a room full of phantoms completely naked. Also, since Kureha doesn't wear a shirt or bra under her leather jacket, a few of her other fight scenes are a minor version of this trope since her jacket is shown occasionally flying open during fights, resulting in her fighting with her breasts fully exposed (though, this is edited out of the tv version).
Later on we also have the appropriately-named rebel army Nudist Beach. They do wear belts and straps to carry their gear, but those don't cover much.
Ryuko, after she abandons Senketsu upon the revelation that she's a life-fiber/human hybrid wipes out a small army of Mooks and then storms Honnouji Academy wearing nothing but a bedsheet worn as a cape. Soon after, Satsuki breaks free of the cell where she was being imprisoned by Ragyo and wipes out some of the same mooks while wearing nothing but a pair of shackles (and fighting with a single metal toenail blade.)
In Blade And Soul, Alka attacks a peeping tom during her bath in episode 1.
Unusual example with Durbe/Dumon from Yu-Gi-Oh! ZEXAL in that while Barian's anatomy is definitely different from human's, he's the only one to lack any form of "clothing"(Vector, Mizael, Nash and Merag) or armor(Alito, Gilag) making this more jarring.
In Outlaw Star, the first time we see Melfina she's stark naked and about to kick some tail with the rest of the crew, who seemed to pay no mind to her nudity. This happens again a few times in the manga.
In Cat Planet Cuties, Aoi and Manami are in the bath when the burglar alarm sounds. Que both girls rushing outside with their guns without so much as grabbing a towel (although Manami does grab her helmet).
"Liberty Leading the People" probably deserves a mention, although she's meant to be the personification of Liberty rather than a literal person.
This is pretty common in Classicism and its successor art-eras: The Rennissance and Neo-Classicism. The idea behind these periods was to show the human form. Because of this, many famous mythological and Biblical battles were depicted with fighters sans clothes. The most famous is probably the various statues of David killing Goliath (or depicted just before or after doing so).
Zarda in Supreme Power. After awakening from a centuries-long dormant state, she wandered into some Italian city, stole some clothes and killed everyone who got in her way (with a lance she broke off a statue, no less).
The Amphibian, a mutant Wild Child who lives in the ocean and doesn't wear clothes, killed a man who shot at her after she saved his drowning girlfriend (he thought the Amphibian tried to kill her).
Doc Spectrum's crystal once took control of him at night and had him confront one of his government superiors naked, because that's how he sleeps.
Also, Hyperion, when he flew so fast he mostly blew his super-suit off, and later his government boss detonated the super-bomb in the military base he attacked. Supreme Power was pretty fond of this one all around, as befitting its Darker and Edgier nature.
Very oddly lampshaded in the last regular issue of Captain Carrot and His Amazing Zoo Crew!, when Gorilla Grodd attacks Earth-C. Grodd looks exactly like he normally does in The Flash comics: a realistically-drawn gorilla. To the cartoon animal population of Earth-C, though, it's a Full Frontal Assault and makes him all the more horrible.
Dwight's first encounter with Manute is this as well. He's just had sex with Ava and Manute has come to take her home. It doesn't go well.
Ultimate Spider-Man loves this trope, though it usually tends to be out of necessity or accidental. For example, Sandman can't turn his clothes into sand, and Electro and the Hobgoblin burn right through their clothes.
Blade gets a reference. It's invoked accidentally when some vampires bust in on the title hero sleeping in the nude. Naturally they crap themselves when he suddenly awakens. Backup comes, but naked Blade tears them to pieces too.
In Secret Six, Catman spends an issues-spanning flashback running around naked (the better to show off his wicked cool scar) and expressing his displeasure towards the poachers that killed some lions. Seeing as this involves teaming up with the surviving lions and forcing the poachers to walk blindfolded through a field of their own traps, he is indeed scary enough to qualify for this trope.
In a later issue he beats up some guards at a zoo while starkers.
Played with in the Titans of Tomorrow arcs of Teen Titans, which features such such curiosities as Robin as a gun-wielding Batman; Superboy as a Superman who calls Lex Luthor "Pa"; and Beast Boy as a feral, nudist Animal Man!
Parodied in The Fabulous Furry Freak Brothers. Back in the 1960's, when airline security was very casual, the Brothers take a plane trip with a carry-on bag full of marijuana. First a hijacker takes over the plane, then a second hijacker overpowers the first, then a third one takes over... eventually, Franklin strips naked and screams, "Take us back to Nashville or I will DESTROY US ALL with what I have in this bag!" (After they make it down safely, they turn down a TV interview, saying, "We gotta go get destroyed.")
Watchmen: Dr. Manhattan is an unusual case. The nudity symbolizes his detachment from the human race, as well as emphasizing his utter invulnerability: nothing can hurt him, so why bother covering up? The only times he bothers to get dressed are at the request of others.
It's worth noting that he starts out in a black bodysuit. As he grows increasingly inhuman, he wears less and less — he's in a thong by The Vietnam War.
Father, the first villain of Warren Ellis's run on Stormwatch. As if being a mass-murdering Implacable Man with no flesh on his face who quotes Nietzsche while killing people isn't unsettling enough, he is also naked, probably as a result of being an Artificial Human recently escaped from the base of his creator.
An issue of H.K., a comic by French creators Jean-David Morvan and Trantkat, features group of naked cybernetic women slaughtering the characters... in explicit detail, from a variety of angles.
Wolverine did this a bunch during the time he was experimented upon at Weapon X, in part to show how he was being dehumanized to the point where human decency wasn't relevant.
And in the Wolverine comic Get Mystique, the titular shapeshifter morphs away her clothes for no apparent reason before loading up◊ with heavy weaponry and going into the final battle wearing an ammo belt and a Slasher Smile.
This happened to Venom a few times, when Eddie was separated from the Symbiote. (Some artists portray him wearing shorts under it, but others are more realistic). The most notable case was during his first limited series when the Life Foundation forcibly removed it, and he had to help Spider-Man fight five mercenaries that had been given Symbiotes spawned from his Symbiote.
Also notable in that series, because it seems to be the only time that the Venom symbiote generates the mass it attacks people with by taking it from that covering Eddie.
A Hulk comic from the 90s, where right after beating the hell out of Captain America, the savage Hulk had a particularly brutal fight with Thor, all while completely naked. The Hulk won.
When Paige Guthrie, aka Husk (a founding member of Generation X and occasionally a member of other mutant teams) uses her powers to turn her body into iron, diamond, adamantium, or whatever to fight an enemy, she's usually technically naked, although the effect itself conceals it.
In his last moments before he got shot, Joe Ridgeway of Locke & Key leapt naked out of his bathtub quoting Shakespeare and hitting the Big Bad with a rocks glass.
In the "The Collective" arc of New Avengers (vol. 1), Alaskan mutant Michael Pointer is literally possessed by the vengeful spirit of a dead Chinese mutant who idolizes Magneto, who also happens to drag along the power sets of all the mutants who were depowered on M-Day. After the initial explosion, which destroys his entire home town, he starts walking to the lower 48 across Canada, obliviously destroying anything and anybody in his path. Throughout the four-issue arc, he is starkers — his clothes were burnt off right at the start. At one point, he grows to giant size.
Burnout of Gen 13 once ended up in this situation when he saw an airplane going out of control and used his fire powers to fly up there, accidentally incinerating his swim trunks in the process.
The Silver Surfer is always naked, although he doesn't possess any visible genitals. A planet-devouring cosmic entity probably doesn't see any need to give his servants the ability to procreate sexually.
Wonder Woman: After Hera finds out that Zeus had an affair with Queen Hippolyta, and thus is Wonder Woman's father, she angrily attacks Queen Hippolyta with an axe while wearing nothing but her peacock-feather cape.
In one storyline, one of the guys runs Sara's character in her absence. After Brian points out that lightening the character's encumbrance lets her attack faster, they carry this to its logical conclusion by having her charge into battle naked carrying nothing but her weapon. This works for a while, but ultimately gets the character killed. Sara is not amused.
In another (one-panel) strip, the players' characters are attacked by a crazed naked man wielding a broken lance. Considering their usual attitude toward NPCs, the Knights are surprisingly tolerant of this.
Bob: Hey, this guy seems pretty kewl. Maybe he'll join our party.
In Stealth Parody fanfic Batman Nemesis Fight by Peter Chimaera, Catwoman pretends to have switched sides so she can have sex with Batman. But then she reveals "That was a trick. I am not good like I said. I am always evil!!" and fights Batman and Robin naked.
In the Naruto fanfiction With Heart and Underwear of Fire, Itachi does this in order to fight Naruto's alter ego Boxer-sama.
Deadpool: Hi, I'm a Marv— [suddenly looks down and to his right]WHOA![static cutaway]
In DC Nation, Hades forced the Titans to compete naked when attempting to win Donna Troy back from death. Part of the reason was to mess with their heads. Of course, Starfire casually drops her skimpy costume, turns to the rest of the bunch and announces they all have nothing to be afraid or ashamed of. Donna also strips, despite being the "prize" rather than one of the combatants because...well, it's the Titans. "Running into hell naked to rescue a teammate" has turned into a Running Gag in Nationverse when describing the team's mentality.
Every Terminator, obviously. (Justified because the androids cannot bring objects with them while traveling through time, including clothing, and as a result, are always naked when they appear in the present day.)
Pinbacker from Sunshine. Made worse as he's covered in 3rd degree burns.
In the 1940 science fiction satire The Invisible Woman, the title character, while able to turn invisible, was naked when she did so (justified because her clothes could not turn invisible along with her) making many audiences at the time regard the film as slightly risqué.
Patrick Bateman from American Psycho will run after you naked with a chainsaw — provided you let him keep his tennis shoes on.
The inhabitant of room 237 in the film version of The Shining.
In the 2007 Beowulf film, after listening to the Queen perform a song, Beowulf begins casually stripping naked in front of her. When questioned about it, he tells her that because Grendel is naked he will fight him naked. Her reaction is priceless. He then goes on to battle Grendel naked as the day he was born.
Mystique is always naked. This makes sense from a sci-fi point of view since her mutation only affects her own body and it works in a sort of reptile-chameleon sort of way, so wearing clothes would simply at the very least be impractical, the 'clothes' she appears to wear are actually a part of her body; she describes taking off these 'clothes' feels like in much the same way a snake sheds its skin.
She appears to form perhaps the basis for the mindset of walking around completely without clothing especially in her natural form throughout X-Men: First Class. When Erik Lensherr tell her that her natural form is beautiful and demonstrates by dropping a barbell on her that it takes more concentration to maintain a fake form to conceal her true appearance than fighting in her natural form and concentrating completely on fighting would and when she tells Hank Mcoy at the end, "Remember Hank, Mutant and proud." right after joining Magneto.
Made all the more curious that he's naked once he escapes - immediately prior to that he was wearing a pair of briefs.
In X-Men: Days of Future Past, Mystique does most of her fighting in her mutant form, with no clothes on. This is lampshaded at one point when she's seducing a target and returns to her normal form, who up until that point was quite excited at the prospect of seeing her naked.
A blink-and-you-miss-it scene in Cthulhu. As the apocalypse begins we see people stripping off their clothes and/or rioting as the protagonists drive down the road; one of them is armed with an assault rifle (the soccer mum who opens up on them with an MP5 moments later is fully clothed though).
In the French filmLa Guerre des Boutons — and the Irish remakeThe War of the Buttons, the boys of two villages are at war. When somebody is captured, they cut off the buttons of his clothing. To avoid this, in one battle the boys attack naked.
In The Hangover, Leslie Chow leaps out of the trunk of their car butt naked while attacking them with a crowbar.
Alice Tseng's character in the Taiwanese movie Ninja: The Final Duel (later edited into 'Shaolin Dolemite') fights off enemies after leaping out of a bath.
In Duel to the Death, some female ninjas whip off their clothes to force a shaolin monk to avert his eyes and be captured.
In the French movie Le Poulpe, a woman is attacked while bathing, but she hears the thugs coming, so she steps out and greets them with a gun. They comment that she doesn't have the balls to shoot them (and we're presented with an uncensored shot from navel to knee as evidence), until one pisses her off and she shoots him in the foot.
In the Bruce Willis film Last Man Standing, the main character gets ambushed while he's in bed; his lack of clothes doesn't stop him from slaughtering his attackers.
Inverted in the thriller Naked Fear. A serial killer (based on real-life murderer Robert Hansen) kidnaps women and then hunts them through the New Mexico wilderness. He strips them naked to increase their feelings of vulnerability and terror.
From 1971 comes an obscure Western called Catlow and this scene that is both a played-straight version of this trope and a subversion of Defeat by Modesty (of the "cornered while bathing" variety, not the "strip off clothes while fighting variety"). And yes, that isMr. Spock kicking ass naked.
The title character of Bronson has a tendency to do this, often combined with greasing up to make himself more difficult for the prison guards to subdue. Despite Bronson being played by Tom Hardy, these are not Fanservice moments.
The Angry Princess from the 2001 remake Thir13en Ghosts. Like the other ghosts of the house, she appears as she did in death — which in her case was brought about by slashing herself with a butcher knife in the bathtub.
The ending of A Serbian Film, when Milos finally snaps from all the hell he's been put through on set and kills the entire film crew while in the nude. He even uses his penis to skull-fuck a man to death.
At the end of Sleepaway Camp, Angela — or should we say Peter — is fully naked and holding the severed head of her last victim. The reason for her notorious expression is because they put a mask on a college student stand-in for that last scene.
The title character in TNT Jackson fights topless.
Alan Bates and Oliver Reed's (in)famous fireside naked wrestling match in Ken Russell's "Women In Love".
In Black Rock, women being chased through the woods by killers are forced to take off their clothes when they get wet to prevent themselves from freezing to death (not played for Fanservice, it's very harsh and realistic). They then use a pocketknife to make spears out of branches and prepare to fight back against their attackers.
Michael Caine, a cockney gangster displaced to Newcastle in Get Carter, sends two thugs packing by threatening them with a shotgun. he then calmly drives them down a street. Whilst stark bollock naked.
The heroine of Sex & Fury has en epic fighting scene "in the nude".
Cammi's husband charges Jack's car au naturel in Sideways when Miles sneaks into the house to steal back Jack's wedding ring. Justified by the fact that the couple are in the middle of makeup sex.
In My Bloody Valentine 3 D, Frank and Irene have sex, but he acts like an asshole afterwards. Irene angrily follows him into the parking lot without bothering to dress and pulls a gun on him. He tells her to put some clothes on and calls her bluff because the gun isn't loaded, but she throws it and nails him in the head.
In the DOA: Dead or Alive movie, the police enter Christy's hotel room while she is showering to arrest her. She flirts and flaunts her body to make them drop their guard, then kicks their asses.
Tarzan was sometimes naked in the original works by Edgar Rice Burroughs, even as an adult. ("Clothing was a hindrance and a bother", claims the character in one story.)
From the same author, this happens all the time in the John Carter of Mars books. There's actually very little attention drawn to it, but it's also made clear that nobody on Barsoom wears any clothes other than jewellery and a harness on which to hang their weapons.
Discworld's The Fifth Elephant has a literary example in Angua's older brother Wolfgang. Wolfgang has the Übermensch-complex in spades, and an assumption that humans are inferior to Werewolves. He does wear clothes on occasion, such as when attending public events, but when fighting or at home he's always naked.
Angua herself did this to a ship full of Klatchians in Jingo, being that she chased Ahmed there as a wolf. Ahmed, being the total not-idiot that he is, ignores the assault and proceeds to do go about things as he does.
In Night Watch Vimes has been stuck in the past and when he's restored to the right time he doesn't have his clothes. Instead of trying to get any, he goes chasing after Carcer immediately.
Heroic example is in a Star WarsExpanded Universe novel: Shatterpoint. Mace Windu is cornered by some Mooks in what is effectively a locker room... who notice to their slight shock that, unlike most people would when confronted naked, he doesn't even flinch. Windu, being the Badass that he is, proceedes to beat the shit out of the thugs.
The Star Wars Expanded Universe also has the Echani culture, a Proud Warrior Race who view combat as a form of communication. Their personal duels, including courtship rituals, involve wearing as little as possible as to not impede movement (which they see as garbling the message). If they have to concede to wearing armor, it is as light and flexible as possible, often backed up by an energy shield (like the fighters in Dune). At least two Echani duelists became Jedi Masters, meaning the style is known to the Order, and probably translated quite well, seeing as Jedi rarely wear armor.
Another Stephen King instance: one of the more frightening "phone crazies" Clay encounters at the start of Cell is nude except for sneakers and is using car radio antennae as weapons.
In Stone of Tears, Kahlan leads a midnight raid on an enemy camp, full of formerly D'Haran soldiers, with her own forces (herself included) naked and painted white, to represent ghosts of an old tribe (which tended to fight naked and aroused) who scared the bejeezus out of D'Harans.
In Silence of the Lambs, serial killer Buffalo Bill enjoys hunting his victims naked in his darkened basement, and does so when going after the hero, Clarice Starling.
A heroic example occurs in the last book of The Immortals, where Daine goes after Ozorne in eagle form. This trope comes into play when she changes back to a human: her clothes don't change with her.
In Nightfall (based on Isaac Asimov's short story), when the titular climax occurs, many people are driven mad and civilization is turn upside down. After the climax, one of the characters narrowly avoids an encounter with a feralized man who hunts other people for food and who wears nothing but a belt in which he keeps his many knives.
Used for comedic suspense in Storm Front. Called out of the shower by an escalating series of unexpected guests, Harry Dresden winds up naked in a situation that just keeps getting worse.
The villains take a turn at this when Harry interrupts a sex-powered magical ritual in progress and the couple who are providing the lust-energy start firing guns at him, still nude.
Subverted in the third Dresden book, Grave Peril. This time, when Dresden winds up naked — in a vampire court's laundry room — he puts on a pair of duck-covered boxer shorts before going into battle. An insane vampire-groupie, however, remains unclad.
In Cold Days, Harry's clothes are disintegrated by Demonreach's wards, and he's naked throughout the ensuing climactic fight. Harry even invokes this trope as a tactic. Fix thinks Harry has had a Face-Heel Turn, and Harry deliberately enrages him because it makes him fight sloppily. He does so by playing up his own nudity and mentioning that he should show Fix's girlfriend what a real man is like, and laughing that it's good that visibility is so low, because Something Else Also Rises.
Jack Vance's Planet of Adventure saga has a memorable Full Frontal Assault. Ylin-Ylan is one of the Yao, a people with an extraordinarily strict code of pride and etiquette — imagine the most exacting dictates of Victorian England melded with the complexities of court life in Ancient Japan. When Ylin-Ylan finally loses it over being slighted in love, she turns up at dinner completely naked, holding a gun and a knife: when she gives up on restraint, she goes all the way.
By the end of Lord of the Flies, all of Jack's tribe has discarded their clothing in favor of body paint. This is more of the animalistic type, though — it's a sign of how far they've broken off from the society they started out in.
Played with by a rather large portion of the Aiel cast of The Wheel of Time have absolutely no problem fighting in the nude when necessary. They do, however, have a problem about fighting without their veil.
In Steel Rain, one of Nyx Smith's Shadowrun novels, a corporate security officer with a samurai mindset is attacked in her apartment by a huge cyborg and chops him into junk. She then makes an emergency videophone call to alert her company's forces to the attack; it's not until the person she calls reacts to seeing her image that the reader learns she'd been butt-naked all through the fight.
In God Emperor of Dune, an army of Face Dancers (shape shifters) ambushes the titular God Emperor by impersonating Duncan Idaho, the leader of his Fish Speaker army. Duncan rectifies this by stripping down. He doesn't actually fight, but he does it mid-battle regardless.
The Modesty Blaise novel The Silver Mistress has Modesty strip naked for her final battle with The Dragon. However, it's justified: he's at least as good at hand-to-hand combat as her, and much physically stronger. So she then greases herself up to make herself that much more difficult to get a grip on.
Caramon the Warrior of Dragon Lance has fought entirely naked on at least one occasion, and frequently wears little more than a Loin Cloth. Being nude doesn't bother him (mostly because he doesn't have anything to be ashamed of), and if you don't have any armor handy, fighting naked is safer than fighting clothed — a piece of loose cloth is something an enemy can grab during a scuffle, or it could get tangled in your weapon, or any number of other things.
Paul's sister Alia fights a training machine while naked in Dune Messiah.
In Ender’s Game, Ender must fight while naked when he's attacked by a bully in the shower.
The Ravirn series has the Furies. As living embodiments of Vengeance, they fight without any regard for human values like modesty. Since they're Nigh Invulnerable enough that they don't need armor or protection against the weather, they don't see the point of wearing anything.
A battle-to-the-death in Dan Simmons' Hyperion Cantos occurs during "the Detective's Tale." Ambushed in bed, Brawne Lamia learns how harrowing — and yet disconcerting to her foes — it is to fight while naked.
The Saga of the Noble Dead has the ancient vampire Li'kan, who fights completely naked in the snow and ice high in a mountain range. Being undead, she isn't bothered by the cold.
In Flinx Transcendent, Flinx removes his AAnn bodysuit to take a covert dip in a small pond, only to be spotted by an adolescent. He's forced to duel the young reptilian in the nude, to keep it from alerting its parents to his presence on the AAnn homeworld.
In Le Donjon de Naheulbeuk season 3 novel (and Comic Book Adaptation), the party is ambushed on a river while traveling by boat, but the attackers are greeted by a naked Elf and her bow. She had actually stripped down in anticipation of an ambush, on the basis that she may have to abandon ship (and as a bonus, it allowed her to sunbathe).
The universe of Space Captain Smith features Wainscott, the leader of an elite commando team. Wainscott fights naked whenever he can (partly to unnerve his enemies), which is unusual for a combat officer in what is otherwise an Expy of the British Empire. He's possibly a shout-out to Orde Wingate; see the Real Life example below.
In Michael Kurland's The Unicorn Girl, this is given a truly unique justification. The characters visit a Victorian-like world where most people cannot even see nudity, a fact which some thieves are very happy to take advantage of. When our heroes get accused of the crime, they end up resorting to a naked escape themselves.
At one point in "Cain" by James Byron Huggins, a super-soldier gets right up from the operating table and proceeds to rip his way through every guard in the secret military lab facility on his way out, clothed only in the blood of his victims.
Karela the Red Hawk in Robert Jordan's Conan the Invincible. Twice. Once while fighting Conan, once while fighting lizard men who attacked her bandit camp. The second time, she was wearing a cloak with nothing under it at the start of the attack, but she removed it and used it as part of her fighting style. She seems to spend as much time naked as clothed in this novel.
Also Sazed gets himself stripped naked and thrown into jail so that he can bust Vin back out.
In the Heralds of Valdemar novel The White Gryphon, Hadanelith, a Serial Killer and Mind-Rapist, conducts a series of assassinations against prominent members of Haighlei society... by climbing into their windows nude. This has several purposes: it shocks the victims, who are mainly high-class females, into being unable to resist; it avoids leaving evidence in the form of scraps of clothing or shoe-prints; it helps frame the White Gryphon delegation since no Haighlei would ever consider such an act; and it amuses him.
In the web-novel Domina, the fey Ladies were always naked, up until they changed tactics midway through the story. A chapter from one of their viewpoints notes that they do it explicitly to throw their enemies off-balance. The Princess of Killing Sparrow muses that nudity is a better weapon than you'd expect, and militaries should train against it. Funnily enough, once they start wearing clothes, people are more disturbed by that, since it means that a group of insane women with armies of monsters at their command are changing unpredictably.
In No Good Deed..., Elsabeth is dozing after a late-night tryst with a wandering minstrel at the inn at Friuli when she's awoken by an assassin attempting to knife her. She throws her covers over him as a distraction and finishes him off stark-naked. With her paramour of the night bewildered by the whole incident.
Live Action TV
In the 1975 TV movie The Legend of Lizzie Borden, Lizzie (played by Elizabeth Montgomery) takes off all her clothes before chopping up her father and stepmother with an axe. This has been suggested as a possible explanation for the lack of bloodstains on the real Lizzie Borden's clothing, which was one of the main reasons she was acquitted. note A more likely explanation, assuming she was guilty, was that the bloodstains were on a dress she is known to have burned a few days after the murders.
Tooms, (a mutant character in two episodes of The X-Files season 1) crawls into people's houses, through ducts and plumbing and such, naked. It was the actor's idea — he realized it was creepier.
In an episode of Malcolm in the Middle, the cadets at the military school are preparing for a survivalism exercise. Each brags to the next about how few supplies he's taking with him (thermal blanket/hatchet/matches/water tablets, thermal blanket/knife/flint, blanket/knife, etc). Badass cadet Stanley walks in, wearing nothing but camo body paint. "Let's rock."
Marbod Whitefalcon (in Yulia Latynina's One Hundred Fields) once took over a castle from inside almost singlehandedly and wearing nothing but his sword; justified in that he was taken prisoner and stripped of all his possessions previously, and didn't have the time to get dressed to preserve the element of surprise after escaping. This whole scene (and the fact that Marbod celebrated by laughing maniacally and eating a chicken while still naked and surrounded by hideously disfigured fresh corpses) still freaked out the Earthman who happened to be in his retinue very much.
Mock the Week: The round was Wheel of News and the subject was "Burglary". Andy Parsons contribution was to admit to sleeping nude as a tactic should he be burgled, as it would be more intimidating than confronting the burglar in "Paisley pyjamas". At the other end of the scale he said the idea could be improved by confronting the burglar wearing a gimp mask and saying "I'm so glad you came!"
In Dollhouse, the first time we ever see Alpha, although he's not attacking anyone, he is naked. Then the camera pans to show us a dead woman and blood all over the floor, implying this trope.
La Femme Nikita episode "War" begins with Nikita in the shower when several Red Cell agents come to kill her. She stalks and dispatches them while still nude.
The Trinity Killer from Dexter. The first kill we see from him is incredibly creepy and completely naked.
Inverted on NCIS, when Tony is awakened by an intruder in his room and Gibbs and Kate rush in, all three drawing their guns. It's an inversion because the intruder is a harmless iguana: a fact that compounds Tony's embarrassment at having his colleagues come at his startled yell, only to find him stark naked (he sleeps in the buff).
In a CSI: Miami episode, a divorce judge was murdered by two boys, one in a relationship with the judge's daughter who stripped naked to avoid blood splashing their clothes when they shot him. Their plan succeeded but didn't work out as well as they wished... should've tested their gun first.
When Jackie is hurt in the line of duty on Roseanne, she acts as if she had faced a hugely dangerous situation. Her partner informs Roseanne that Jackie actually reached for a naked drunk man's equipment thinking he was going for a gun. He then tackled her and rolled down a flight of stairs with her. There is no end to her teasing.
In another episode, Roseanne begins to have an argument with their neighbors. Basically, they're nudists, and Roseanne and Dan are trying to convince them to plant a hedge to block their windows because they're really, really old. The couple tell them to basically get over it and don't look if they don't want to see it. Roseanne mentions that it kind of hard not to. When the couple says rather bitchily that they could, Roseanne simply retorts, "Oh, yeah?" '''(Rips open blouse.) "What color are my eyes?" The old couple run screaming from the room.
In Angel when Cordelia, possessed by Jasmine is revealed to have killed Manny, the group theorize she must have stripped off her clothes as there was no blood on them and she wouldn't have had time to wash or had another change of clothes on her (see Real Life below).
In Justified, Quarles strips naked before torturing and sexually abusing Donovan, whom he is holding captive in his bathroom. Also, while Boyd's prisoner at Audrey's, Quarles opens his robe to annoy Jimmy. After Jimmy leaves the trailer, Quarles wraps a chain around Minerva's neck and threatens to strangle her, while his robe is still open.
In True Blood, the Shifters, Werewolves, Werepanthers, etc cannot take their clothes with them when they transform, so they end up fighting nude at least once.
In Boardwalk Empire, Bugsy Siegel attempts to kill Gyp Rosetti while he's having sex. Rosetti is full-frontal in the resulting gunfight (in which he uses his girlfriend as a human shield), and then strides through the carnage covered in blood and swinging free. It's strangely awesome.
Warhammer 40,000 has a few examples of naked or nearly-naked combatants, including the Fetish Fuel of the Sisters Repentia, the horrors of the Arco-flagellants, and the Sealed Evil in a Human Can of the daemonhosts. Of course, these three are in the same army at the same time, and their entire purpose is to die so their souls can be redeemed (hence the lack of armor). That's Warhammer 40K for you...
Daemonettes, the typical daemons of Slaanesh, are occasionally seen fighting almost completely naked, though the most common offender of this is the Slaaneshi Keeper of Secrets, basically giant woman/demon-like giants with crab-claws and multiple swords.
Ciaphas Cain fights a Slaaneshi cultist who sports leather thigh-high boots, gloves, and face mask... and that's about it. It's implied that Cain fights several cultists in a similar state throughout The Traitor's Hand. Then again, as followers of Slaanesh, public streaking is the least of their offenses...
The Kroot have sense organs spread about their body and decentralized genitalia, so they prefer to go about nearly naked to better feel the environment. They only wear some straps and pouches for holding things, and maybe a few small ceremonial items.
Dark Eldar Wyches have skimpy outfits as a general rule, and they tend to get skimpier as the Wych's battle prowess improves. The most skilled fight almost in the nude.
Heshon, the Lost Atlantean Goddess of the Wilds from the RPG Scion, is described as an attractive, naked wild woman with bird talons.
The members of clan Gangrel usually aren't keen on wearing any clothes.
Battlebabes in Vincent Baker's Apocalypse World RPG can have an ability called Impossible Reflexes that protects them from harm when unencumbered; the actual rules are Armour +1 when wearing normal clothes, and Armour +2 when naked or nearly naked.
GURPS has the "Bulletproof Nudity" optional rule, for a certain kind of cinematic game — the less you wear, the harder you are to hit. For many players, this rewards you for dressing your character up in cheesecake armour. For a certain kind of player this rewards battlefield streaking.
The Deathlord known as the Bishop of the Chalcedony Thurible has a "war form" that actually exaggerates this — not only is it naked, it sprouts multiple sets of genitals. Not many people like the form (once described by a snarky freelancer as a "monster made of dicks"), but it's there.
The Melkin Fool in Red; a Solar Night Caste who was captured, tortured and converted by the Lover Clad in the Raiment of Tears, she looks like a harlequin... Except she doesn't wear clothes. Try not to think too much about about it.
Lunars are also likely to do this, for all of the reasons mentioned above. Depending on personality and circumstances, of course.
In some early editions of Dungeons & Dragons nymphs can actually use their nudity as a weapon. Their beauty is so great that even seeing a clothed one can render a mortal blind, and seeing one naked can be literally fatal to the viewer. (This was eventually changed in later editions; nymphs either focused their beauty as a sort of overwhelming aura, or in the most recent edition, didn't have powers based on their beauty at all. Seduction and trickery, however...)
In The Book of Mormon, General Butt-Fucking Naked earned his name by committing atrocities "butt-fucking naked." When preparing to deliver an Ass Shove to one of the protagonists, he starts stripping his clothes off. He's based on the real General Butt Naked of Liberia.
Mentioned but not shown in Jade Empire: one of the Black Whirlwind's exploits before joining your party was singlehandedly storming an enemy fortress "piss-drunk, buck naked and screaming like a maniac" in his words. It's heavily implied (or outright stated) that this worked because the soldiers thought he was crazy. Checking his journal during the battle where you control him directly reveals he has a checklist upon waking, one of which is "do I have clothing?" And how to handle the inevitable fight if there is no clothing.
Also mentioned but not shown in TimeSplitters: Future Perfect. In the second level (1928 Scotland), Captain Ash says, "In the best tradition of the British, I suggest a full-frontal... dahhh, assault, that is." The game is full of double- and triple entendres.
Pigsy, the criminally insane, chainsaw-wielding maniac from Manhunt. Don't worry, he isn't completely nude... he's wearing the decapitated head of a pig as a hat.
The Shade class in Anarchy Online was added to the game during its first expansion. All classes in AO get a class specific type of armor. The Shades'? Their class specific armor is nanite laced tattoo ink. In other words, Shades in their class armor fight essentially naked covered in magic bodypaint. Barbie Doll Anatomy abounds.
The Diseased in Penumbra (although they are heavily mutated by that point).
Governor Vicus Cassus from Clive Barker's Jericho, who doesn't wear a stitch of clothing. This is made worse by his extreme obesity, and the fact that his stomach is slit open vertically (which he uses to help him attack — he pulls his stomach open and spews the contents of his intestines at the protagonists).
Alexia Ashford from Resident Evil: Code: Veronica, when she mutates. She is completely naked, with monstrously large veins covering her lady bits.
Resident Evil 2 features naked male zombies, although their genitals aren't visible, possibly due to the graphical limitations of the time (or maybe they just... fell off).
The Werewolves in The Elder Scrolls III: Morrowind's Bloodmoon expansion would attack the player while naked. This wouldn't have been an issue if they didn't attack you while human.
Although Kratos from the God of War series never appears entirely naked, during the design phase the developers realized that he became more primal and aggressive in appearance when drawn with less armor (and less hair).
The monsters appear mostly naked as well. In one of the bonus features, Dave Jaffe explains that he wanted the monsters to be like wild animals, which meant making them naked. The gorgons got to spend the whole game topless, but they weren't able to keep the penis they modeled for the cyclops (Jaffe remarked: "Poor cyclops").
It is up to debate what, if anything, Seth of Street Fighter IV is wearing. Some assume he's outright naked.
Dante's Inferno pushed the limit to this; in the circle of Lust alone, we've got nearly-naked concubines with tentacle stinger clitorises coming out of their groins, and the circle's boss, Cleopatra, has naked breasts with vagina-nipples that spew knife-armed babies from them. Oh, and Satan himself is naked and packing giant, um, equipment. The only thing that could have made it scarier is if they had gone whole hog, and made Lil' Satan into the phallic dragon head it was in ancient depictions of the guy.
Saiki in King of Fighters XIII. He is the first boss in the series history to be fully naked. It should be noticed that he doesn't start fighting in the nude, but after killing and absorbing his Anti-Villain subordinate Mukai, his white suit poofs and from then on he's buttnaked, with his black flames covering both his face, his hands/feet and his crotch.
The Europa Barbarorum mod, where the "Gaesatae" unit fight in the nude, and generally kick ass unless you have javelins or arrows.
In the original game, the Spanish, Gauls, Germans and Dacians can all train a unit called Naked Fanatics. They are Exactly What It Says on the Tin, and the unit description makes this point abundantly clear. For the sake of keeping the 12+ rating, however, their actual skin has them wearing loincloths (although one of the Germanic units in the Rome: Total Realismmod was actually naked in-game).
Throughout the entire level "A Thousand Cuts" in Kane and Lynch: Dog Days, both Kane and Lynch are bloody naked, literally.
The Brood Mother(s) from both Dragon Age games especially "The Mother" in the Awakenings expansion. The Desire Demons are topless as well, and tend to feel themselves up while talking to you.
In Knights Of Xentar, the main character starts out totally buck naked due to a really bad case of Honor Before Reason as well as being hung over that leads to him being stripped entirely of his equipment. And then he beats those thieves who robbed him single-handedly afterward while still being naked. Unfortuntely, he never gets his equipment back.
Near the end of the final case of Phoenix Wright: Ace Attorney — Trials and Tribulations, Maya suggests that Godot can't be the killer because he would have gotten blood on his clothes (and not had any opportunity to change them). Phoenix suggests this trope as an explanation, but Godot points out that it was way too cold for that.
Anything inorganic that's brought to Improbable Island has a good chance of turning into something else, so everyone who goes there is sent naked. It's feasible to fight naked for the first few levels before buying armor (and much later in the game, if your character becomes part-cat, you'll actually get advantages from fighting naked.)
Fatal Frame III has the Tattooed Priestess, who is topless for the whole game. However, since her whole body is covered in dark blue tattoos, this doesn't mean much. Also, you'll be spending too much time running the hell away to look too closely.
The sequels to Saints Row give the player the option to fight naked, though your naughty bits are covered up in pixels. In fact, in the Saints Row: The Third mission "Pimps Up, Hos Down", the Boss ends up fighting his way out of a Morningstar brothel while stark naked and high as a kite, and in Saints Row IV you fight your way out of captivity on Zinyak's ship while completely naked. Saints Row: The Third originally had a "Nude" customization option for your gang, but it was Dummied Out.
In the non-censored version of The Witcher, you fight several types of naked female foes, from hot, floating vampires to fat, sagging, old witches.
Demon-lady enemies from Castlevania usually don't wear anything more than a pair of knee-boots. Maybe a corset, but that depends on the game. The official art for the Succubus in Castlevania: Symphony of the Night has exposed breasts with defined nipples.
There is an achievement in Half-Minute Hero for defeating three Evil Lords wearing no equipment. Although the only way to do this is to be under a pact with a demon, and you'll kick all three Evil Lords' asses whether you have equipment or not.
Outlast has the Twins, machete-and-cleaver-wielding cannibalistic lunatics who are also completely nude. This makes trying to hide from them all the more tense, as no clothing means they barely make a sound while stalking the asylum.
Seems to be a recurring element in the (extremelyNSFW) webcomic Electric Retard, probably because the ax crazies in question have a tendency to rape and/or defecate on their victims. Plus it would be difficult to find clothes that would fit Giant Naked Hitler.
Heroic example in Fite!: Guz normally wears armor, but when he and Lucco were attacked while bathing in the river, he didn't bother to put it (or anything else) on, he just grabbed his sword and shield and started fighting. (Lucco elected to pull his trunks on.)
Leo in VG Cats regarding his underequipped D & D alter ego; "I shall astound then with my NAKEDNESS!"
His Prince of Persia impersonation also quickly veered towards this. His response to a scratch on his shirt? Rip the whole shirt sleeve off. Oh, now it's asymmetrical. Better take the other one too. What's that? The shirt is ruined? You're right. Better take it all off. "Sexy, no?" Aeris left the moment he began contemplating a scratch on his pants.
Rider: My dress is indulgence of my predilection for a bit of modesty. Philosophy at its most ornamental. Reality requires only my sword.
One of Sam Sorenson's first acts when he got on the island for Survival of the Fittest was to strip down to his nothings and proceeded to go on a naked rampage...
Viktor Kurchatov from v3, his entire body covered in scars and missing genitalia, was caught by Will Sigurbjornsson and Julie Mikan nude and eating the corpse of Karl Van Buren. Viktor responded by screaming "I am the master butcher!" and moving toward Julie to try and kill her, only to be shot AND stabbed in the head.
Played for laughs in an episode of Sponge Bob Square Pants where Plankton switches places with Mr. Krabbs thanks to a reality-altering device. Plankton wears the pants at the Krusty Krab, and Krabbs takes his place trying to steal the formula — butt naked.
The same thing happens on an episode of The Plankton Show, where Plankton uses the same device from the former, but this time switching lives with SpongeBob.
The Flesh from the Kablam! short "Action League Now!" is "super strong, yet super naked." However, unlike most other characters who fall under this trope, he's not insane or villanous so much as heroic and goofy.
Pam is seen about to have give a beating to Malory in the end of Archer episode El Secuestro after taking her own top off. Bonus points go to Pam, as this shows off the terrifying third stanza of The Destruction of Sennacherib tattooed on her back under thirteen tally marks.
In episode of Matts Monsters, the protagonists had to fight a monster that stole clothes, forcing them fight him in the nude.
Oddly enough there was a good REASON to fight in the nude... Before modern medicine, the majority of deaths from combat were caused by cuts and stab wounds getting infected. Often this was because the weapon forced a scrap of clothing into the wound, where it would fester... If you aren't wearing any clothing, this can't happen!
The Celts would sometimes charge into battle naked, and the Picts upped the ante by painting themselves blue (and "Pict" actually means "painted" in Latin, so that's why they're called that). It effectively scared the crap out of the Roman legions, since they knew that if a guy wearing blue paint was charging at them completely naked he probably wasn't afraid of them. Even better; their wives, girlfriends (and sometimes boyfriends) would get them "excited" before a battle. So picture a Roman legion, far from home, and down the hill come dozens of men, all painted blue, with RagingStiffies. Unsurprisingly, the Romans said "screw it," built Hadrian's Wall, and tried to ignore the clearly insane barbarians.
In a similar vein with the Celts, Viking berserkr (from which we get the word "berserker") would charge into battle either covered in bear or other animal skins, or completely naked.
There is a video of a man on PCP, totally butt-naked leaping onto a cop car. In full view of the camera. It's on TruTV.
And early episode of COPS had officers having to deal with a large, bald, sweaty naked man. They remarked how it is a bit hard to get a grip.
During the brutal Liberian civil wars, many fighting bands took to wearing strange outfits to instill fear in the enemy. "General Butt Naked" (Joshua Blahyi) went into combat naked, and led a band of soldiers called "The Butt Naked Brigade". Their whimsical name belies the horrifying atrocities they committed. And the naked soldiers of the Butt Naked Brigade were children.
This was at least partially a case of deliberately invoking the trope, though there was also a kind of quasi-religio-spiritual rationalization for it (mainly for those soldiers who were thinking "You want me to go into battle naked?"). It was basically a kind of "clap your hands if you believe" invulnerability; anyone who didn't believe enough in their invulnerability to fight in the altogether would turn out to not be invulnerable. (As a side bonus, you could explain any naked deaths by saying that they didn't believe strongly enough, and they weren't around to contradict you.)
The original natives of the Canary Islands (the Guanche) would walk into battle with just a spear and a handfull of sharp stones... and they still managed to slaughter an army of conquistadors once.
According to Vietnamese legend, during the Trung Sister's rebellion (A.D. 43), male Chinese soldiers fought naked in order to shame the female rebels. Official Chinese history denies the claim, but then they barely recognize the rebellion at all.
This was never proven, but as stated above, it has been suggested that Lizzie Borden removed her clothing before using an axe to kill her father and stepmother, so as to avoid getting blood on her clothes and making her guilt obvious. (Indeed, if she was the killer, the common way she is portrayed in the media — as a lunatic — is likely inaccurate. There was almost no evidence linking her to the crime, making it seem like it was well-planned.)
The 1806 duel between the Earl of Barrymore and Humphrey Howarth was averted because the earl could not bring himself to duel with Howarth, who had prepared for the duel by undressing. The earl thought Howarth was making a farce of the duel, but in fact it was justified, as Howarth had been an army surgeon who knew that the worst thing about gunshot wounds was the risk of infection caused by bits of clothing in the wound, rather than the loss of vital organs.
During some Hawaiian luaus, male volunteers are given a very skimpy grass skirt to put on during one part of the show. While the volunteers naturally put them on over what they themselves have on, the emcee informs the audience that ancient warriors only wore the skirts.