Kamina. As one of our own has put it: "Kamina has no shirt. Kamina NEEDS no shirt." The one time he did doesn't count due to the local Lotus-Eater Machine— also the Kamina with a shirt was a blatant fake.
Simon for the entirety of the Lordgenome arc and the final battle against Anti-Spiral.
The aforementioned Lordgenome for 90% of his screentime.
The manga lampshades this in an early Yonkoma, pointing out that Leeron is the only one of the cast that actually wore a shirt at that point in the story. You Don't Want to Know why that is, or at least that's what Simon decides.
Urek Mazino from Tower Of God. Maybe not that great an idea, because then everyone can see that he had his own name tattooed on his back.
The anime-exclusive villain Valgaav from the third season of Slayers: first half of series: flimsy top that exposes most of his chest and all of his midriff. Second half: no shirt. And in a flashback of him in his past: no shirt. Seriously, he's allergic to shirts.
Ryota Kajiki/Mako Tsunami from Yu-Gi-Oh!, which The Abridged Series naturally lampshaded ("I like that he doesn't wear a shirt"). Back when Yami/The Pharaoh was... well, alive, he also was one — along with pretty much everyone in Egypt. Odd, considering how much sun there was.
Truth in Television; the fact that it was so sunny was precisely why shirts would be impractical (you would overheat too quickly in them, and robes weren't always practical or acceptable). Sunburn wouldn't be a problem.
Grimmjow Jaegerjaquez, whose finely sculpted abs draw about as much attention as his blue hair. He might as well not be wearing a shirt at all with the amount of coverage it provides (and that's before the Clothing Damage strikes).
In later manga chapters/episodes, the fans are treated to Kensei Muguruma who has an open shirt to expose the 69 tattooed on his finely sculpted abs. Tite Kubo is a sadistic bastard.
In the (filler) Zanpakuto Strange Tales Arc, the spirit manifestations of Ruri'iro Kujaku and Kazeshini are constantly shirtless.
Avirama doesn't wear a shirt, or anything else on his upper body for that matter, save for a pair of Detached Sleeves.
Both Sasuke in Part II (who is lean, but moderately muscular) and the Raikage (who is utterly freaking ripped) have very open shirts, and the latter takes his off completely when fighting.
Sasuke actually has a functional reason for his not-shirt; it's so his Cursed Seal form's wings don't rip his clothes every time he uses them as they erupt from his back. When Itachi removes this ability, Sasuke reverts to more standard clothing.
On the other hand, Zabuza doesn't wear anything on his upper body but the strap of his sword holster and some arm-warmers (except for some flashbacks to when he was still with the Mist Village and he wears a standard flak jacket).
Utakata, the container of the Six-Tailed Slug (believe it or not he's a bishounen) wears his kimono half open, revealing his chest and, if it weren't for his strategically placed soap-container, much more.
We see in a flashback that Hanzo used to fight shirtless because he can release poison from a venom sac he implanted in his abdomen and clothes apparently make it hard to release it.
And let's not get started on Hidan, who can't be troubled to wear a shirt or button up his cloak all the way.
Sanosuke Sagara from Rurouni Kenshin is a lean, mean, shirtless fighting machine!
Both Greed and Ling in the manga wear vest/jacket-type things that nevertheless leave their chests and tummies nice and visible. Foreshadowing?
In Chapter 104, after Father absorbs God, he ends up looking just like Hohenheim. Specifically, a half-naked, teenage Hohenheim. And he spends the next several chapters like this too. Quickly turns into Fan Disservice after Hohenheim's countermeasure strips him of the souls needed to comfortably contain his new power, causing unsightly, bulging veins to pop all over his body.
Creed from Black Cat has his chest constantly exposed due to the ridiculously gayinteresting clothes◊ he wears. And when he's not a Walking Shirtless Scene, it's because he's butt naked.
In the manga Shaman King, HoroHoro's battle outfit is just shorts and a long, sleeveless, unbuttonable coat, but he tends to spend a lot of time sporting only bandages and his boxers. When he's not having a bath with all the other guys wearing only a towel. On another hand, Ren is a repeat offender (bathes completely naked even with other people), Hao is shirtless under his poncho and Yoh's uniform shirt is always unbuttoned, but they're not as bad.
Johnny Rayflo of Vassalord. Also seems physically incapable of buttoning up his PANTS.
Crow of Deadman Wonderland occasionally wears a coat, but doesn't seem to want to button it up.
Shichika from Katanagatari. Upon removing him from his secluded island home, Togame took him to a clothing store in the hope of doing away with his ragged, half-naked state. He somehow left the store with an outfit that covers even less.
Several characters from Sakigake!! Otokojuku wear their uniform jackets unbuttoned with no shirts beneath.
South Carolina of The Statetan-Project never wears shirts or shoes. Even during the Civil War. Seriously. Apparently this exposure works very well, since a certain Virginian can't keep her eyes off of him...
In Wild Rock, the young men of both clans never wear shirts. Emphasized further by wearing necklaces, arm warmers, loincloths and leg warmers, all which just serve to frame their bare torsos.
Marco Owen in King Of Thorn. He loses his shirt fairly early on and never bothers to replace it, thus giving us a good view of all the tattoos he got whilst in prison. And later, all the scars he's gotten as a result of his fight with one of the Zeus Race/dying/being resurrected.
Gunnm: Zekka's outfit consists entirely of boots, pants and a vest that he is physically unable to button, all leather. Toji'sgi is also always much too loose on his chest. Largely justified in that not only are both epic levelmartial artists, but in that settings about 90% of population are Hollywood Cyborgs, so they don't need clothes in the first place.
The lack of Brock from the Pokémon Special manga is preposterous. He's shirtless just like the original sprite of the game.
Any number of loincloth-wearing barbarian heroes, most notable of whom is Conan the Barbarian. Averted in the original Conan stories, where he usually wears armour or clothing appropriate to the environment.
DC Comics' Hawkman, most of whose costumes leave his whole chest bare except for a logo and some bondage-y leather straps to attach his wings.
Like Hawkman, Martian Manhunter usually wears nothing on his chest except crisscrossing red straps.
Navis from Sillage spends the entire first album wearing nothing but a loincloth, making her a female example, at least temporary.
Rogue, and for that matter all GIs, in Rogue Trooper aren't even given shirts when sent into battle. Justified in that the Norts have scanners specifically designed to detect Souther armour, so going shirtless gives them a stealth advantage. Still, you'd think some sort of breastplate would increase their ability to kill enemies.
Sally Frickin Acorn from Sonic the Hedgehog. It is most notable when she is drawn by Spaz or Steven Butler.
Sgt. Nick Fury, in his days with the Howling Commandos, almost never had a uniform shirt that made it through an adventure intact.
Seems quite natural, albeit not universal, among the aquatic Wavedancers of ElfQuest. In the first book of the Original Quest, all grown male Wolfriders wear what amounts to open-to-the-belt, sleeveless shirts, apart from Cutter and Redlance, who wear open, short vests instead. Rayek of the Sun Folk has it down to an elaborate collar. The fashion has become less ubiquitous with later costume changes, but remains popular.
All The Smurfs (even Sassette, who wears overalls without a shirt) except Smurfette are a non-Fanservice example of this trope.
Tai Lung of Kung Fu Panda is perpetually shirtless, which certainly counts as Fanservice for the Furry Fandom. Granted, the combination of thick snow leopard fur and all the sweat-inducing kung fu training would seem to make a lack of a shirt a given (he was even shirtless in flashback as a cub!), and we also get treated to shirtless Po for the entire movie. But this walking CMOA certainly seems to have the right to parade around half-clad.
To further illustrate the point, note that in the Kung Fu Panda "Warrior's Guide" (a blatant reference to the various guidebooks to Star Trek and Star Wars), on the pages devoted to Tai Lung, arrows point to him to call attention to his "broad shoulders" and "bulging biceps".
Apparently, Aladdin couldn't afford buttons for his vest. Or a shirt. Or nipples. The Genie also is completely shirtless.
In the first Lilo & Stitch movie, Nani's love interest David doesn't put on a shirt until the epilogue, and even then only because it was snowing.
Tarzan, especially when the title hero is an adult man.
Being an animated swords-and-sorcery film with art style by Frank Frazetta, Fire And Ice is filled with topless (and nearly bottomless) barbarians. The blond Larn and the masked Darkwolf are most prominent, and the villain Nekron wears an open robe that he removes when he duels Larn and leaves off for the rest of the movie.
Films — Live-Action
The ironically-named "Shirts" in The Sasquatch Gang is always bare-chested. His brothers and father are also bare-chested — first thing his father does when entering the house is to remove his shirt.
How many stills are there out there of Jacob Black/Taylor Lautner with a shirt on? Or any of the other male actors playing werewolves in that movie, for that matter?
According to Chester A. Bum, they all suffer from The Curse of the Missing Shirt.
Lampshaded in Eclipse, where Edward asks: "Doesn't he own a shirt?"
Lampshaded in Valentine's Day, where the character played by Taylor Lautner is offered a new shirt, starts changing shirts but stops less than halfway through saying that he doesn't want to take his shirt off in public.
Originally, the film was going to have a scene where his character simply walked into school and took his shirt off. Lautner rejected that for being overly blatant Fanservice.
In Surfer, Dude Matthew McConaughey chose to be shirtless throughout. He doesn't wear much on top in Reign of Fire, either.
The entire male cast of Spartacus: Blood and Sand (except John Hannah), but especially the title character. When it comes to this TV series, being a Starz series and all, there's even a female version of this as some brief scenes in Batiatus' Household show some servant girls whose attire has obviously them being topless in a non-erotic context i.e. as they go about their duties. This TV series LIVES on this trope.
Most of the male characters on Buffy will find some excuse to start stripping. Particularly Angel.
Played for laughs in the 1986 soap opera parody mini-series Fresno, where one character was literally named in the credits as "The Man With No Shirt". The IMDB lists him as "Torch", and he was played by Gregory Harrison. At one point, Torch goes back to his room to get a fresh white T-shirt; he doesn't put the new one on, just carries it in one hand, as he did the previous one. At a costume ball, he is a bare-chested centurion, and is surprised that one of the female characters—perhaps Carol Burnett's—recognizes him so easily despite his face-concealing helmet.
The male Feeders of Vaal in "The Apple" episode of T.O.S.
The no-shirt-guy (Needuss Attention Showum Nipplus) who finds any excuse to go without a shirt and show off his muscular, hairless upper body was featured in the Museum of Annoying Guys on The Man Show.
Quite a few of the men in Mystere qualify as this at some point (i.e., the aerial cube and hand-to-hand performers), but the most obvious example is with the recurring character Red Bird, as when the role is played by a man the costume leaves the chest exposed. This is spoofed within the show when the clown Brian Le Petit encounters him — as soon as the bird has danced off, Brian mockingly mimics the dance and opens his shirt for a quick moment (that Brian is a Cool Old Guy just makes this funnier).
Alegria has the handbalancer, flying man, and aerial high bar performers going shirtless; the fire spinners and cyr wheel performer also have most of their chests exposed.
The handbalancer in Zarkana. Technically he has a shirt, but it's so short it leaves his midriff bare, and his contortions quickly expose the rest of his chest. By his act's end, the shirt's off completely.
Illidan Stormrage is always without a shirt. Even more so after he absorbed the powers of the skull of Gul'dan, which made him grow wings on his back, which means he cannot wear shirts anymore. (As thisDark Legacy Comics strip mentions in the second panel.)
The other Demon Hunters throughout WC3 and World of Warcraft seem to have adopted his sensibilities as well. Except, for the obvious reasons mentioned above, for the one female Huntress in World of Warcraft, not that she wears much.
Same thing for Blademasters in WC3 and WoW, Grom Hellscream included. Ironically, in terms of gameplay, the Demon Hunter and Blademaster had the highest armor scores out of all the Hero Units in the game.
Another character who goes completely shirtless is Hawkeye from Rekka no Ken (released in the US and Europe as simply Fire Emblem. And that's just his character art: all barbarian-class sprite art is shirtless.
Also in Bad Moon sign, after accidentally mutilating the torso stick figures would be oblivious to, the gnomes kindly teach you to identify it for free.
Legacy of Kain: Kain, at least in his adult form. In fact, going topless seems to be the fashion de rigueur for male vampires. Raziel and his brothers trade shirts for leather pants and a half-cape, and Janos rocks the No Shirt, Long Jacket and the bare-chested look in turns.
Nier from NieR Gestalt, showing off how ridiculously ripped he is. Kinda weird seeing as how he is the father of an adorable little girl and, besides fighting the legions of darkness, grows watermelons in his free time.
Mortal Kombat has Johnny Cage, Liu Kang, Jax, Sub-Zero (MK3 only), Nightwolf (MK3 only), Jarek, Kai, Reiko, and of course Goro, Kintaro, and Shao Khan. The furries get Motaro. Combine with the Stripperific likes of Li Mei, Kitana, Mileena, Jade, and Khameleon, and it's actually fairly balanced in its Fanservice.
In Prince Of Persia The Sands Of Time and Prince Of Persia The Two Thrones, the Prince starts out wearing a shirt, but as he acquires Clothing Damage loses it. In Sands of Time, he tears off his sleeves one after another as they're damaged, and after falling into a hole shucks the rest of his top. In Two Thrones, he skips the sleeves part, falls into a hole, and wakes up shirtless. From thereafter, in both games, he just runs around barechested.
Golden Sun Dark Dawn: Ayuthay seems to have "shirts omitted" in its male dress code. The guards may or may not wear armor, but neither the king nor his nephew wear anything on top. The latter, for protection's sake, dresses up before leaving the castle. Eoleo, another player character, comments that he never saw anyone from that place wear "real clothing" before.
Almost every male character in the obscure PSX beat-'em-up platformer Tai Fu: Wrath of the Tiger falls under this trope, both friend and foe, including the title character himself. And that's a LOT of bare chests, considering that every character except one or two of them is male.
Sima Zhao wears a jacket, but leaves his chest bare.
Badass Grandpa Huang Gai, meanwhile, just wears various straps and shoulder pads on his upper torso in almost all appearances.
Gan Ning is topless in his default attire in both 7 and some other installments of the series.
Aarbron from the Shadow Of The Beast trilogy. The first two games (in which he is a beast, then a beast-man) have him in just a Loin Cloth (except for the Sega CD version of Shadow of the Beast II, which gave him a breastplate). In the third game he is fully human and wearing modern clothes, but still shirtless (the opening depicts him with a shirt, but his in-game sprites are clearly lacking).
All of the Qunari in Dragon Age II, apparently because they were survivors of a shipwreck and lost their armor. By the third act of the game, Merrill says she's sad that they left, because they were "easy on the eyes."
The title character of Guy Spy and the Crystals of Armageddon, spends the whole game in an open vest with no shirt (except for the Switzerland section, where he wears a coat, averting Exposed to the Elements). In one scene, he takes off the vest (for no apparent reason).
Weaponlord reaches a record by having every male character in the game (four sevenths of the entire cast) not wear a shirt. The other three are women.
The title character of Tomba in his first game. In the second, his default outfit is still shirtless, but he can acquire a variety of other costumes that give him special abilities and cover his torso.
The shirt-free male barbarians in Puzzle Quest 2 can, like everybody else, buy extensive armor. And like everybody else's, it never appears on their avatars.
Given Free Country, USA's lax clothing laws (and also because it's called "Free Country"), characters in Homestar Runner are not required to wear pants (or any clothes). Strong Bad is one big Walking Shirtless Scene; he thinks it's better to show off his abs. Homestar has had his shirt removed a few times, but nobody knows if he wears pants or not, so...
Mell: Artie, you spend most of every storyline with your clothes off.
Numerous examples in Glorianna, including Portai, Ravi, Gith, Thanaktos, and the Mountain King.
Oran from Broken Saints, who is shirtless for half the series. Also, although Kamimura always wears his cloak, he never has a shirt on underneath.
Benzaie provides this in Suburban Knights, since he dresses as Conan the Barbarian. Cast commentary demonstrates how much he suffered to bring us this fanservice, given the film was shot during April in Chicago.