Kevlard

"Your sword only pierced through my belly fat and one kidney: a flesh wound! Have at you, sir!"

—Animorphs

In fiction, fat is more than just a sign that the character is out of shape—it's body armor. A fat character will often be resistant or even entirely impervious to damage because of their layers of blubber. Punches will be absorbed or deflected, often with a comedic BOING, and in rare cases, bullets or other projectiles will be diverted.

In Real Life, of course, fat usually isn't quite so powerful a defensive aid. It might add some cushioning against a punch or two, but it does nothing against a bullet. However, characters with Kevlard seem to bypass this downside entirely. They might even go out of their way to build up fat so they can fight more effectively.

Kevlard often, but not always, overlaps with Acrofatic and/or Mighty Glacier. More often than not, it's applied to villainous characters rather than heroic ones, usually because it's meant to be an intimidating display of size trumping skill. Often played for laughs, and almost always a set-up to having the characters discover the Achilles' Heel of the tub of lard in question. Usually, in its less serious incarnations, the ability to repel damage with fat is presented as being some kind of inhuman superpower.

It's important to make the distinction between this and Mighty Glacier: Mighty Glacier characters are simply those who are big and slow, and it more often applies to huge, muscled characters. Kevlard, however, specifically refers to the body armour properties of pure lard, not muscle.

Examples of Kevlard include:

Anime and Manga

In One Piece, during the Black Cat Pirates arc, the Meowban Brothers are hit with the swordsman Zolo's Finishing Move. It nearly slices the skinny one in two, but the fat one survives.

Zolo: "All that blubber saved him..."

Mister Heart is one famous example from Fist of the North Star. He was, in fact, the first enemy shown that Ken couldn't simply kill in one blow; his body fat protected him from Ken's fatal Finger-Poke of Doom. Ken had to resort to kicking Heart a hundred times in a second just to force the fat out of the way before striking forward with his killing blow.
Chouji in Naruto can use a jutsu to do this—somewhat justified, as he turns into a huge sphere of fat, and it's quite reasonable to assume his actual vital organs are somewhere in the center.
- His father can use a more advanced technique that turns him into a proportional giant. Chouji later learns how to increase the size of individual body parts.
- Kabuto at one point wonders about Tsunade (a powerful ninja with astounding large breasts) if her fatty breasts absorbed his attack.
Kurita of Eyeshield 21 has this mildly. The average high schooler can't really hurt him, but a lot of the linemen he plays against are around his size and can do plenty of damage.
Fat Man from the comic series Ratman has this as a literal super power. He can control the fat in his body to allow him to do things such as block knives.

Comic Books

The Blob from X-Men has this as his superpower - he's Nigh Invulnerable Fat Bastard who can make himself literally immovable.
Subversion: In the Marvel Universe, Kingpin appears to be a monstrously obese man who appears to harness the power of Kevlard. However, once he actually takes off his shirt and starts fighting, it's apparent he is ripped as hell, thus making him a Mighty Glacier instead.
Subversion: a RoboCop comic book had a minor villain that appeared very fat. Lewis tries to drop him with a standard double-tap, just for the villain to shrug it off and casually gloat that what looked like fat was actually custom-made body armor made to look like fat. Lewis addresses this problem by wrestling him to the ground and pressing the barrel of her sidearm square against the center of his forehead. "Wanna try that trick again?"

Film

Po in Kung Fu Panda is an average fighter overall, but his secret technique relies on his sheer mass to absorb attacks. By the end of the movie, it becomes Chekhov's Skill as it renders him immune to Tai Lung's paralyzing nerve strikes.
The fat guy in Three Ninjas: Until the heroes figured out where his weak point was, their blows simply did not register.

Literature

In Monstrous Regiment Sergeant Jackrum claims his fat is like armor, and that a man once stuck a sword in it up to the hilt, and was very surprised when he got nutted in response. Of course, Jackrum said that as part of his recruitment spiel.
In Charles McCarry's The Bride of the Wilderness, the character Gustavus Hawkes is able to keep going on with an arrowhead in him—albeit with considerable pain—because it's stuck in his subcutaneous fat. McCarry attempts to justify this by claiming that unusually dense fatty tissue runs in Hawkes's family; an ancestor took a small-caliber bullet with similar aplomb.

Live-Action TV

Mad Men mentions a fat girl in Sally's class whom the other kids poke with pencils because they think she can't feel it.
MythBusters tested the viability of this against bullets in their second "What is bulletproof?" special. When using a layer of fat equivalent to what the fattest man their researchers could come up with would have had protecting his vital organs as a baseline, the bullet went right through both the layer of fat and the simulate for the internal organs. The Mythbusters thus conclude that fat could eventually stop a bullet, but not in anything human.
In an episode of Manswers revealed you need to be over 1000 lbs for your fat to be able to stop a bullet from killing you.

Oral Tradition, Folklore, Myths and Legends

In The Bible, Eglon, the king of Moab, gets stabbed by an Israelite in an assassination attempt. He's so fat that the Israelite pushes the sword into him, blade, hilt and all, and it doesn't come out the back. (Judges 3:12) He still dies, though.

Recorded and Stand Up Comedy

Chris Rock has a "Government Hates Rap" bit where he goes on about how few rapper murderers have been convicted, despite the killings taking place in prominent places and\or taking a long time to execute. For Biggie Smalls he posits that "there must have been some reloading in that drive-by".

Tabletop Games

Dungeons & Dragons gives us a feat aptly called 'Obese' in the Book Of Vile Darkness. It increases constitution by 2 at the expense of dexterity, thus increasing your endurance.]
A disadvantage of same name in Savage Worlds gives you notable amounts of all-important stamina at the cost of movement speed. Some builds can really abuse that.
The Grael from Fifty Fathoms, being a race of seal-people, have a natural layer of blubber, which is thick enough to act as armour.
A scenario for the Judge Dredd RPG had literal Kevlard in a new variant of Boing! (a type of very resilient rubber plastic you could encase yourself in then bounce improbably far and fast) called Spunng! being developed. It consisted of a drug that when ingested converted all subcontaneous fat to a type of Boing! - a group of four really fat guys take it and go on a crime spree - flattening anyone who gets in their way by bouncing into them at high speed with bullets just bouncing out of their Spunng! enhanced bodies. However Spunng! was highly flammable rendering them very vulnerable to incendiary (if not bounced out), high explosive or laser fire.

Video Games

The Adjudicator in Demon's Souls qualifies, although the Meat Cleaver stuck in his chest was a pretty good indicator of where you had to hit him.
Punch-Out!!! is full of these.
- King Hippo is one of the earlier video game examples. He was completely immune to being knocked out until you figured out you were supposed to hit him in the rather obvious bandages.
- Bear Hugger and Mad Clown, both fat boxers, are nearly immune to body blows. You have to punch them in the head to damage them. Punching them in the stomach results in a boing, and the boxer mocks you. If they taunt, their midsection is vulnerable, and hitting it will stun them.
Bob from Tekken purposely gained weight so he could have this advantage.
There are enemies in Scott Pilgrim Vs. The World: The Video Game that repel attacks using their prodigious girth.
In Dwarf Fortress, fat realistically serves as a layers of tissue that may take damage from an attack instead of a more important body part. More bizarrely, in Adventure Mode you can repeatedly set yourself on fire and put it out after a while to remove all the fat in your body. If you survive you become effectively fireproof because heat does not kill you through burning, it kills you by melting tissue (which except at very high temperatures is usually fat) to make you bleed to death.
Temperance (a morbidly obese zombie) from House of the Dead 4. Even though you could actually stop him from attacking you by shooting his head, it was impossible to do any real damage to him via your bullets. You had to drop a clock on his head to beat him.
Team Fortress 2: The Heavy Weapons guy has both the biggest girth and the most hit points of the nine classes.
In What Did I Do to Deserve This My Lord, "Fat" monsters can evolve if you starve some of your monsters to death. Fat Lizardmen, in particular, are incredibly durable compared to the garden variety lizardmen, with nearly double the amount of hit points and defense.
In reference to Heart's example, fat enemies in Fist of the North Star: Ken's Rage have a separate health track representing their bulk that must be depleted before they can actually be harmed.
This is how Bear Druids, in World of Warcraft, fulfill their tanking role. Other tanks have shields and weapons to block and parry oncoming attacks. Bear Druids have neither, but have substantially more armor rating (especially through talents like "Thick Hide") and health points in order to simply soak up the damage. Oh, and to do this, they literally become bears.
The Lard powerup in The Binding of Isaac makes Isaac fat, and raises his maximum HP.
Black Bull in Shadow the Hedgehog is an enormous, flying beast with one eye and several layers of blubbery fat. Attacking its eye is the surest way to bring it down, as its fat makes it mostly impervious to damage. (Mostly because attacking its body still causes damage, but at a slower rate than attacking its eye.)
This is probably how Dr. Eggman survives the destruction of machine after machine.
Pokémon definitely seems to like this one. Snorlax in particular is very much this trope, though in a slightly strange way. It does have loads of HP, as you would expect, but its SPECIAL Defense is its other strong point, while its physical Defense is lackluster.
In Dungeon Keeper Bile Demons are so obese they're spherical, take up 4 tiles in a Lair where most creatures take one, eat a lot, and are very slow. However their health is miles beyond any other creature you can access without advanced buildings, and they're immune to slap damage.
Overwatch has Roadhog, the only tank in the game who doesn't bother covering his huge belly (let alone wearing armor) and still has the highest health in the game, on par with D.va's mech.
In Kingdom Hearts, a Large Body is a huge, fat Heartless who cannot be harmed if attacked from the front, as its huge belly deflects all blows, although striking it there when it makes a charge attack stuns it for a few seconds.

Web Comics

In Problem Sleuth, Ace Dick's "Auto-parry" technique involves taking the attack in the gut.
- Also, Sawbuck of the Felt from Homestuck can take a lot of damage, and hops through time every time he's hit by something.

Web Original

According to SOTF-TV's lore one of the previous winners of a season was one Archibald "Archie" Stewart, who took a ridiculous amount of punishment over his run. The official explanation was that the layer of fat he had on him lessened the impact of what appeared to be grievous injuries. Subverted/deconstructed, when after he won he was unable to leave the shopping mall he was fighting in due to the cumulative amount of injuries and had a near-death experience in the hospital.

Real Life

Sumo wrestlers generally have this ability. This is partly because, in Japan, sumo wrestling is not so much the comedic butt of sports jokes as it is in the West, but a sacred sport with many hallowed training rituals. Participants sequester themselves away and eat for hours at a time while also building huge amounts of muscle. The result is that you get 400 pound fighters who appear practically indestructible.
- Any training regimen that emphasizes strength would also lead to an impressive amount of fat due to the way human muscles work. Lean, "dry" physiques excel in speed and agility, but are nothing to write home about in the strength department. Sumo is a strength-based martial art, and even if some wrestlers are rather Acrofatic, that's really accidental to their brute strength. Thus is the "weightlifter" build of most rikishi.
The Gladiator Games of Ancient Rome too. Despite the Sword and Sandal stereotype of relatively lean, muscular gladiators, historic gladiators lived on fat-building diets. The layer of fat helped protect them from the bloody, slicing wounds that audiences loved.
When someone gains weight, their internal organs do not grow bigger. They are nigh-literally a skinny person surrounded by fat. Stab a fat person in the gut with a short knife, and you'll simply be unable to reach anything important. Of course, getting stabbed will still cause a great deal of pain, and not-insignificant blood loss, but is less likely to be a mortal wound.
Seeing that most weapons and even martial unarmed strikes are designed to go right through the human body and its fatty layers, this trope makes for a rather poor defense against even primitive weapons, never mind the likes of firearms. If anything, the added weight is going to slow a man down and hurt his stamina, making it more difficult to defend via evasion. An exception to the rule is wrestling, where the extra weight does help both to maneuver an opponent, or prevent an opponent from maneuvering you.
- Samantha Lynn Frazier says hello from Atlantic City, NJ.
A lot of polar creatures have a thick layer of blubber under their skin to handle the cold climate better. The walrus' blubber, helped in part by its thick hide, is thick enough to withstand several tuskings from rival walruses and stand a better chance against polar bears.
In 2008, an obese Australian woman was infected with necrotizing fasciitis, AKA flesh-eating bacteria, a deadly infection that rapidly destroys tissue and can kill within hours. She survived in part because her extra fat gave her more flesh the bacteria could destroy before it would kill her.
Although fat is a risk factor for stroke, heart attack, or aneurysm, a fatter person is more likely to survive one than a thinner person who also succumbs.
In humans (and dogs), being extremely lean (like "ripped" models or Greyhounds) has disadvantages that go beyond being first in line to die in case of starvation. It's very hard to be comfortable if you are nearly fat free.
- Fat isn't just built in armor (even if unimpressive), it also plays a minor role as padding. Without any (or realistically, a very low level of) fat, just the act of sitting down comfortably would need lots of cushioning or else it will feel like your bones being rubbed against something hard -- an unpleasant experience for most.