In comics, this move is most famous for Batman. After the end of the Batman TV series, it became apparent the campy tone had burnt out, and DC realized a change was needed quickly. With Denny O'Neil's writing and predominantly Neal Adams's gothic and realistic art, Batman was made a darkly fearsome night stalker much like he was in the original stories before he was softened for kids. Later, in the mid-80s, Frank Miller's Batman: The Dark Knight Returns overclocked this to dangerous levels.
The shift also carried over to Batman's Rogues Gallery, most notably The Joker, who had been written as a comical "Clown Prince of Crime", but now returned to his psychotic murderous roots and building up one of the largest body counts in the DC Universe (only being outdone by alien societies and villains with near-god level power).
In the '90s the Batgirl mantle was passed from Barbara Gordon to Cassandra Cain, a character who came complete with a much darker origin (she's a mute trained from birth to be an assassin) and a costume that wouldn't look out of place at a BDSM club. Fortunately, she was written well enough in her own series to not come off as ridiculous, in particular being one of the most moral and kindly members of the Bat-family despite her grim background and sinister look.
Jason Todd as Batman is similar to Azrael: a thuggish, heavily armored Batman who guns criminals down with his pair of pistols. Fans have taken to calling him "Gunbats".
From Death of the Family, a number of people might laugh and say that Joker can't possibly achieve this trope at this point. They would be wrong, because his treatment of Harley Quinn is even worse than it was before! Though given who she is...
Not even the mantle of Robin is safe from this "dark and edgy" obsession. Tim Drake whose era as Robin is probably most similar to Dick Grayson, gets replaced by the dark and edgy Damian Wayne. Ironically, Tim Drake was an aversion of this trope by replacing the dark and edgy Jason Todd as Robin and right at the cusp of the Dark Age of Comics no less.
The New 52 remade Mr. Freeze in this fashion, because apparently his Canon Immigrant status as a Tragic Villain from Batman: The Animated Series didn't work with the rest of Batman's Rogues Gallery being psychopaths and lunatics. In this new iteration, Freeze and Nora were never married; Nora was frozen in cryogenic stasis in the 1920s for a heart condition, Freeze merely worked at the storage facility where her capsule was kept and became obsessed with her, leading to his physiology-warping accident. Also, Freeze's obsession with freezing things and ice manifested when, after his mother fell through some ice and almost died as a little boy, he subsequently took her back and pushed her back into the freezing-cold water.
Speaking of Alan Moore, he actually did a Darker and Edgier reboot of UK superhero Marvelman as well. What had originally started out as a British Captain Marvel rip-off, turned into a gritty, Total Recall-ish, what-is-real head trip, that even turned his Freddy Freeman-esque sidekick Kid Marvelman into a violent psychopath.
The Transformers: Generation 2 comic books, loosed from even the moderate Contractual Immortality restrictions they had been operating under before, promptly started massacring the cast. Issue #1 cover copy: "This is Not Your Father's Autobot." #2: "Fort Max Gets the Ax." #3: "Killing Frenzy." The characters would also kill without hesitation and use guns that weren't their signature weapons.
Here's one way to kill the party: Turn cheerful, bouncy Robbie Baldwin from the playfully heroic Speedball into an apparent murderer with a guilt complex worthy of Angel. Now he calls himself Penance, and wears a suit with 612 built-in points of pain, one for each person killed that day. His new powers can only manifest when he is in pain.
In Thunderbolts, however, Penance has come to terms with the Stamford incident not being his fault. He reveals to Nitro the real reason for the suit.The suit wasn't for Robbie, although his survivor's guilt led him to wear it as a form of cutting, it was for Nitro. Robbie captured Nitro in Latveria to punish him for the Stamford incident, put him in the suit and proceeded to beat the CRAP out of him, after which he removes the last spike from his own chest to symbolize that he's freed himself of guilt.
He later returns to the Speedball identity as an instructor at the Avengers Academy, but retains his more serious demeanor. He leaves the school after finally coming to terms with the Stamford incident, and has since appeared in Nova with his previous cheerful personality restored. He still occasionally uses the Penance helmet though, as it's apparently the only way he can access his pain-based powers.
Much of Marvel's Ultimate Universe runs in this vein. A stunning amount of the process of its "updating" traditional Marvel characters for the modern era has involved inflating the sex and violence content (e.g. the Hulk isn't merely violent or even murderous, but is also cannibalistic; Quicksilver isn't just very protective of his sister the Scarlet Witch, but is in a sexual relationship with her; Tony Stark is a genius as expected — due to a painful cancer-like affliction which has spread brain matter throughout his body and will soon kill him). "Updating" personalities means turning everyone into a complete and utter Jerkass. Spider-Man largely escaped.
The biggest example of this in the Ultimate Universe is Captain America, who in the 616-universe is the embodiment of American ideals and values, including but not limited to equality, openness to political discourse, and dedication to international harmony. Ultimate Cap is a sexist hardliner who calls the French cowards. His characterization is more of a Deconstruction of the original idea: a man who's been frozen in ice since the 1940s and yet has to be the quintessential American hero for today, despite being the hero of (and thus holding ideals from) yesterday. Or rather misshapen approximations of the ideals of yesterday, since the whole 'the French are cowards' concept didn't enter popular American consciousness until after WWII and a man from the forties who fought alongside French resistance fighters shouldn't hold that idea. Given that anti-French sentiment in the US hit a peak after 9/11, it's more like he had ideals of a modern subgroup of the populace.
Captain's America's enemy, the Red Skull, who was arguably already the most evil character in all of comic books is even worse. He began his career by killing 200 of his own men and cutting off his face. He forced a woman to kill her husband or else he would kill their baby. He kills the baby anyway. And he's Captain America's SON.
In Cataclysm, it's even lampshaded; with Vision noting the bleaker tone of the Marvel Universe when compared to the 616. Galactus also notices it.
Said Ultimate Universe spread to the 616-universe, as far as evil Iron Man and Reed Richards and Cyclops expelling Xavier from the X-Men (even though Cyclops utterly bombed as Top Guy at the school as far as Xavier saving the X-Men's asses during the Messiah Complex X-Over) and starting his own murder squad, a move even Wolverine found distasteful and only agreed to lead to try and keep Scott from turning Wolfsbane, X-23, and Warpath into soulless murderers.
The whole "Professor X is no better than Magneto" creep from the Ultimate to the main universe that was exemplified by Deadly Genesis, where it was revealed that Professor X led a team of X-Men to their deaths in rescuing his original team from Krakoa and just mind-wiped everyone into forgetting that it happened and trying again with another new team. And that Professor X later realized that the Danger Room was becoming sentient, but ignored it, leading to Danger being created years later.
This all came to a head with the finale of Avengers vs. X-Men, where Cyclops snapped and killed the Professor while possessed by the Phoenix Force. Now he's on the run with his own team of outlaw X-Men, and has already clashed with the Avengers and his former friends. Fittingly, he and Emma Frost have ditched their old costumes for black leather duds. The ultimate irony is that now Wolverine is the more passive of the two. He's disbanded the X-Force and now runs the Jean Grey School for High Learning, where he trains the next generation of mutants. He's also being depicted as a more traditional superhero in Uncanny Avengers.
The current example is somewhat zig-zagged, however, as Cyclops' team has arguably returned to the old 'hated and feared' roots and Wolverine regularly comes off as thoroughly sanctimonious and holier-than-thou, which, considering his past, is more than a little hypocritical. He's not alone in it either, something which, after Battle of the Atom, Kitty Pryde, moral centre of the X-Men, calls them out for. Indeed, Cyclops' team is arguably still fairly idealistic - specifically, when Magneto reprimands Teen Jean for trying to mind control Teen Angel into staying with the O5, he says, "That is not what Charles Xavier taught you, young lady!"
A 2004 Thunder Cats mini, Thundercats: The Return. Lion-O gets trapped in the Book of Omens for five years, and when he gets out he finds the Thundercats beaten, Bengali killed and enslaved by Mumm-Ra. Like Wilykit and Wilykat. Let's just say that puberty has been good to them, and that Mumm-Ra has the same tailor for his slaves as Jabba the Hutt. There is also implied rape of Cheetara by the Mutants. And then there's Lion-O brutally breaking the neck of an ape mutant.
The Supergirl from Krypton is her origin story. In the original Silver Age version, she lands on Earth and is found by her cousin who sees that she is being taken care of (even if his methods are questionable). The Post-Crisis Story Arc involves kryptonite meteors, fanservice, a paranoiac Batman and Darkseid kidnapping her and brainwashing her. On the plus side, Superman immediately wanted to take his cousin in and introduce her to Lois.
At the beginning Kara was a naive, innocent, sweet newcomer. However she grows up during the Silver and Bronze Ages, and although she never stops being an idealistic hero, her childlike innocence goes away. This is made clear in Adventure Comics #424, in where she wears sexy clothes while trying to get a scoop.
When Supergirl was rebooted in the Post-Crisis continuity, several writers and editors thought the best way to update the character was turning her into a mood-swinger, self-centered, bratty jerkass. This strategy continued until DC realized that Supergirl's fans hated it. Supergirl's earlier characterization was retconned out and she became a troubled, insecure but ultimately good and heroic teenager again.
Post-Flashpoint Supergirl started out this way, with Kara being a reluctant hero at best, traumatised and, like most teenagers would under her circumstances, feeling overwhelmed and simply wanting to go home. She also holds a fairly dim view of humanity at large, but considering that they keep shooting at her and have poisoned the atmosphere with Kryptonite. Grief morphed to rage, partly under the influence of being manipulated and betrayed by H'el, and she became a Red Lantern for a little bit. Now, however, she's discarded the Red Lantern Ring, has come to terms with her losses, matured and become that much wiser. She has since accepted Superman's charge to be Earth's hero in his stead in The Final Days of Superman and Supergirl (Rebirth).
One of the flashpoint events leading to this was Wonder Woman's killing of Big Bad Maxwell Lord.
The Superboy-Prime saga, which climaxed in Infinite Crisis, was followed by an even darker and edger storyline called 52, and also saw the relaunching of numerous series with a generally darker tone. A prime example is Checkmate; issue #1 featured a team of superpowered spies infiltrating a Kobra base and leaving no survivors (with the badass heroine of the series, Sasha Bordeaux, shooting the Kobra Big Bad dead, execution style). The series muted its violence considerably after the first half-dozen issues.
While not generally darker and edgier as a whole, the New 52 titles are divided into groups, such as "Batman", "Superman", "Justice League", etc. Two of the groups are known as "The Dark" (supernatural titles) and "The Edge" (titles about anti-heroes).
Blue Beetle was originally a fun book that didn't take itself too seriously - for example, the scarab was played as a Heroic Comedic Sociopath. In the New 52, it was initially just a sociopath, and Jaime couldn't rein it in as much as he used to at first.
A literal version shows in Teen Titans, with the character Solstice. Prior to the New 52, she was a cheerful girl with light powers. Afterwards, she had a permanently inhuman appearance and shadow powers. In addition, Kid Flash has become a murderous rebel leader from the future, Raven is secretly working for her demon father, Wonder Girl now gets her powers from an Artifact of Doom, and Superboy is the clone of Superman and Lois Lane's evil son from the future - though in his own series, the latter became very much a traditional hero.
This ultimately is brought in for a Deconstruction, courtesy of Geoff Johns and DC Universe: Rebirth #1, who shows that no one likes a world filled with Darker and Edgier ideas, especially when it's the heroes who are hit with this. This is driven home with the revelation that Dr. Manhattan of Watchmen is the cause of all of this, having turned the pre-Flashpoint universe into the New 52 universe and seems utterly confused as to why it isn't working. It also serves as a Take That! to those who use the spoilered title as a manifesto to writing comics and not getting the message it was giving out.
Dare, a 1991 take on Frank Hampson's iconic British 1950s space explorer Dan Dare. The 1991 version was written for Toxic magazine by Grant Morrison, and illustrated by Rian Hughes. Dare awakes in the 1990s to find that Britain has become a capitalist society, and that a thinly-disguised parody of Margaret Thatcher has sold Britain to the evil Mekon. During the course of the story all of the main characters are killed - Digby even has his arm blown off - and the final edition ends with Dare blowing up London with a nuclear bomb.
Parodied extensively in the Belgian comic De Kiekeboes, where in one issue, The Simstones, a character from the comic buys the publishing rights to the comic (very meta) and introduces a darker and edgier style.
Marvel Year In Review 1993 parodied this in their own titles, by taking characters that this had been done for, and then making new characters that turned it Up to Eleven:
Spider-Man (Super hero with the proportionate strength of a spider) — Venom (Obsessed lunatic with the proportionate strength of a spider) — Carnage (Crazed serial killer with the proportionate strength of a spider) — Bile (Cannibalistic madman with the proportionate strength of a spider)
Captain America (Liberalistic flag-waving symbol of democracy) — U.S. Agent (Extremist right-wing hard-nosed American) — The Patriot Missile ("Blow all them foreigners to hell and let God sort 'em out!")
Thor (Norse God of Thunder) — Thunderstrike (Norse God of Thunder from Brooklyn) — Godhead (Convinced he is God. Holed up in his compound, waiting for Ragnarok)
Wolverine (Savage killing machine with the soul of a Samurai) — Sabertooth (Uncontrollable, savage killing machine with the attitude of a psychopath) — Clawjaw (Unhousebroken, uncontrollable killing machine with poor bodily hygiene)
Iron Man (High-tech armored Avenger) — War Machine (High-tech armored Avenger with an attitude) — Terror Device (High-tech armored Avenger with two attitudes and Plausible Deniability)
Green Hulk (Mindless rampaging monster) — Gray Hulk (Intelligent rampaging monster) — New Green Hulk (Intelligent rampaging monster with a big gun) — Red Hulk (Intelligent rampaging monster with a big gun and razor-sharp claws)
New X-Men: Academy X. After House of M, the title was hit by Darker and Edgier hard, but the change was especially marked in contrast with the first half of the series. Under Weir and DeFilippis, the book was fairly light-hearted fluff that focused on relationship drama. When Kyle and Yost took over, dozens of students were immediately blown up, and everyone else was left traumatized by their failed rescue attempts. Then a main character was shot in the head and killed. And another main character betrayed the team, was mutilated, and died. They were replaced by a former assassin Tyke Bomb. Succeeding plotlines saw the entire team sent to HELL, one of them tortured and spending a lot of time crying herself to sleep, and so forth and so forth. In fact, most of Kyle and Yost's work falls under this trope. See also: X-Force, mentioned above.
DC's Vertigo imprint revolves around material intended for mature audiences. After the success of Swamp Thing, Doom Patrol, Hellblazer, Shade, the Changing Man, and Animal Man, all of which starred fairly obscure characters from established DC canon, there were a few misfires - up to and including a brooding, psychological take on Brother Power, the Geek. For the uninitiated, Brother Power is a human-sized hippie rag doll given life and super strength by magic sunshine who once ran for a U.S. congressional seat and was last seen orbiting the Earth. Someone tried to make that serious.
Similarly, Grant Morrison himself tried to revive Kid Eternity in a darker and edgier fashion. Kid Eternity was a demi-angel who could summon the spirits of dead famous people. All told, it actually worked out surprisingly well; the miniseries sparked a (short-lived, but still) ongoing by Ann Nocenti, if that's any indication.
Superman: Earth One was explicitly advertised as being darker, sexier, and moodier, and many standard elements of Superman's story are given a darker spin — for example, Jonathan and Martha are forced to keep Kal-El a secret after government agents secretly impound his spaceship in a secret base, Krypton's destruction was a deliberate act of war, and Superman's more angsty than other portrayals and is distrusted by the public... but despite that, there remains a core of hope, with Clark realising that the people of Earth had a reason to be afraid (after that fear was exploited by Zod (here, Zod-El, Superman's uncle)), and comes to something of an accommodation with the United Nations. The rest of the Earth One line plays it very straight, however, as among other things, Bruce Wayne isn't as skilled as other versions and is originally solely about bringing in the man he believes had his parents killed to justice, Alfred is the family's bodyguard (not their butler) and encourages Bruce to kill, Jim Gordon is a reluctant Dirty Cop, Diana is a Child by Rape between Hercules and Hippolyta and Hippolyta originally kept Diana for the purpose to enact a war against all males, Starfire is the source of several Titans' powers thanks to STAR Labs (led by Cyborg's villianous mother) experimenting on them, the Green Lantern Corps is already gone by the time Hal Jordan gets his power ring—though things improve on that end thanks to Hal, Hal himself is more jaded and cynical, and the last Guardian is insane.
The comic started out as a Gag Series similar to Adventures of Sonic the Hedgehog. Around issue 20 or so, it shifted to a more serious, interconnected tone similar to Sonic SatAM. The Endgame arc (where Sonic becomes a fugitive after being accused of killing Princess Sally, and Robotnik is Killed Off for Real) is where it dove off the deep end, and established itself as one of the darkest incarnations of Sonic, dealing with themes such as abusive relationships, birth out of wedlock, drugs, genocide, and bigotry. It stayed that way for 10 years or so, before Ian Flynn took over as writer and returned the comic to a lighter tone, though still not as light as the recent games. Coincidentally, the darker period from issue 50 to 160 is widely regarded as the series' Dork Age, providing an example of Tropes Are Not Good.
Way back when the comic was humor-oriented, the cover for issue #4 parodied this by promising an "all-new, darker, grittier" Sonic. Turned out he was just covered in dark grit from cleaning the chimney.
Parodied in issue #10 of the old Chip 'n Dale Rescue Rangers comic book. In it, the Rangers are brought to the set of a movie featuring a dark-and-gritty version of a superhero squirrel puppet who originally appeared in a Sid And Marty Krofft-type children's show. The character's creator is shown working as the movie's creative consultant and is not at all happy with the way the movie portrays his creation.
Life with Archie: The Married Life presents stories from the "future" in which Archie has grown up and gotten married, and now has more realistic, adult-sized problems to deal with. It's so dark that Archie gets killed in the final issue.
Afterlife with Archie sounds like a funny concept: Archie meets the Zombie Apocalypse. The series is anything but funny. You know something's up when there are Cthulhu references in an Archie comic. It's drawn in a dark realistic style and the first issue has Hotdog being hit by a car and dying. Jughead gets Sabrina to bring him back but he's brought back as a zombie. He bites Jughead and...
One of those stories, "Secrets of the Deep", was a pretty standard scuba-diving-shipwrecks-and-sunken-treasure adventure... in which an evil treasure hunter shot at the gang with a spear gun and set an electric eel on them!
The above story wasn't even the only Archie comic to feature face-melting action. From 1972 to 1974, Archie published a Sabrina the Teenage Witch spinoff, Chilling Adventures in Sorcery as Told By Sabrina. It had the odd combination of straight-up horror stories with art in the familiar Archie house style. One story in particular stands out, featuring a boy who teases a stutterer at school. The kindly teacher happens to be a witch, and gives him an enchanted book that melts his face off, and possibly kills him! The story probably violated several rules under The Comics Code, but somehow gained the CCA seal of approval (perhaps because Archie ran the CCA?)
Chilling Adventures of Sabrina is in a similar realistic art style as Afterlife with Archie and has the same writer. It emphasises the horror aspect of Sabrina The Teenage Witch heavily.
Archie vs. Predator sees several supporting characters from the series getting gruesomely killed by the titular Predator, firmly planting it in this territory compared to the main books. Interestingly enough it's also something of a case of Lighter and Softer too, since as opposed to both Afterlife and Chilling Adventures it isn't played as seriously and several bits in the book are played for (very dark) laughs primarily from the sheer bizarreness of seeing the Archie Gang mix it up with the Predator of all things.
Paperinik New Adventures is a rare case of this done well. Those stories are way darker than the ones on "Topolino" (the Italian magazine where it is usually published): Paperinik stops fighting the Beagle Boys to defend the Earth from aliens, time travelers and crazy AIs, creating a new roost of supporting cast and using weapons which are much more powerful. However, he remains a very optimistic hero, and the comic gives us several funny and heartwarming moments to balance the mood.
Disney Italy does this as an habit. Aside for publishing some 'normal' stories with classic characters and settings with darker themes, once in a while they bring back Doctor Vultur (a Nazi in everything but the name orango trying to Take Over the World) and a truer to the origins version of the Black Spot, and, in chronological order, they created the following: Paperinik himself (theorically Donald Duck's superhero alter ego. In practice even his lighter stories show the sadistic streak that in two occasions prompted him to set off lynching mobs), Paperinik New Adventures, Mickey Mouse Mystery Magazine (where Mickey is forced to temporarily move in a city more corrupted thanGotham and survive in spite of his very existence being a danger to the men who control the city), W.I.T.C.H. (where the heroes have no qualms in trying and killing their enemies), and Double Duck.
Godzilla: Kingdom of Monsters is this to the entire Godzilla franchise. How dark is it? Godzilla reduces Japan to rubble in the first two issues. The rest of the series has the monsters tearing apart civilization and bringing out the worst of humanity.
However this actually brings it closer to the tone of both the original film and the Heisei era. One of the complaints people had about the series was that, even with that knowledge in mind, it was little too much of a tone shift. Especially in reference to the scene of Rodan eating a child alive. There's another dark scene where Godzilla lets loose his atomic ray on a bunch of people trying to escape Los Angeles which he was currently destroying at that time.
The European G1 My Little Pony comics are darker than the toy-line and American cartoons. While they were usually cute and fluffy, they delved into certain stuff other parts of the franchise wouldn't. The most infamous issue had an explanation for the Twinkle-Eyed ponies. They were enslaved by a wizard and forced to live in darkness so long they went blind. Applejack accidentally pushes the wizard to his death and saves the ponies. The rescued ponies end up using the jewels in place of eyes, and that's their backstory for characters like Fizzy.
IDW's My Little Pony: Friendship is Magic comic series is noticably darker than the animated show it was based on. Issue #3 starts with Queen Chrysalis (who by herself is portrayed much more sinisterly here) and her changelings invading a little town of cute loving kitties and sucking all the love out of them. One month later the whole land is converted into the new changeling kingdom.
My Little Pony: Fiendship Is Magic #1 is perhaps the darkest G4 comic to date. Highlights include the Body Horror of Sombra's transformations, his shattering of Amore after turning her into Crystal, and the Star Crossed Lover story between Sombra and Hope. In contrast to the usual comics and show, there is very little humor in Sombra's tale; it's pure tragedy.
Suske en Wiske now also has it. The new spin-off/reboot series. The first album entitled Amoras features partial nudity, swearing, blood, substance abuse and a mature theme. The series is written als a multi-album story. So far, critics like it. But old time fans expecting the milder tone of the original series will be in for a very unpleasant surprise.
The new series was actually announced to the press as an obituary for Wiske, making it very clear that she dies in the first album. In fact, her death scene is the first album's front cover. Look Here.
Image Comics' March 1993 one-shot Darker Image is this, featuring the first appearances of Dark Age of Supernames heroes Bloodwulf and Deathblow. It is also notable for containing one of the first appearances of The Maxx.
Really, Image tends to be this compared to Marvel or DC. Mainly due to the emphasis on creator freedom, thus there's a lot more leeway for mature content that the Big Two won't allow.
Parodied in an Astérix one-shot with the conceit that they were fulfilling reader's suggestions, one of which (pictured) was to add Steam Punk elements, give them all guns, draw them in a less childish style, and have them talk in a more naturalistic way rather than just punning all the time. The characters are shown drawn in a hyperdetailed Dark Age style (Asterix's feathered helmet wings are replaced with bat wings) with Gross-Up Close-Up-type details on the normally cuddly characters; Obelix is wearing a Badass BandolierPistol Whipping Romans with a BFG in a missile stockpile (Asterix is phoning Getafix to tell him these new gadgets don't work), and everyone is engaging in dreadfully-written Pulp Fiction-esque Buffy Speak, rendered in the UK English translation as Geordie (and still making a wholly unnaturalistic Hurricane of Puns).
Before this were a few twists on dark storytelling in the series; Asterix in Switzerland's plot involves the heroes' efforts to save an innocent from murder. Quaestor Vexatius Sinusitus' potential death offered a jarring but refreshing sense of drama to the otherwise frivolous comedy strip. The same story also contains a more serious look at the Romans than usual - normally, Asterix villains tend to be Punch Clock Villains, Ineffectual Sympathetic Villains or just ordinary people who happen to get in the heroes' way (occasionally even Designated Villains, Played for Laughs), but Varius Flavus's actions (corruption, insane decadance and poisoning his opponents) are much more like what evil Roman patricians in history actually did. Oh, yeah, and an actual Roman orgy (if limited to eating like slobs, getting drunk and hideous makeup) is depicted.
Stories featuring similar moments of deadly menace include Asterix and Son, where the village is burned to the ground, and the impending threat of Orinjade's execution in Asterix and the Magic Carpet. Also Obelix All At Sea, in which both Asterix and Obelix almost die (and the villain does, breaking Nobody Can Die), and Asterix and the Picts, which involves Scarpia Ultimatum and a much more complicated plot than usual. To a lesser extent, The Roman Agent and Caesar's Gift are both about just how ridiculously awful living in their Quirky Town would be.
In Uderzo croqué par ses amis, a compilation album of short stories drawn by various artists about Uderzo, one story is a realistically-drawn, historically-accurate, painfully serious take on the concept of a pair of Gaulish warriors fighting Romans using magic potion. For instance, the magic potion appears to be a kind of religious Magic Feather, they put the skulls of dead Roman soldiers around their village to keep them out (like the historical Gauls did), and they murder Romans with swords. It turns the usually ridiculous little Gauls into something quite dramatic and mystical and badass.
Uderzo croqué par ses amis also has another story in a similarly realistic art style, but with the usual characterisations of the Gauls. The story contains a gag where Asterix and Obelix accidentally catch Vitalstatistix in flagrante delicto with a hot blond who is not his wife, which is depicted in intentionallySquicky detail (since Vitalstatistix is both a beloved childhood character and a fat, ugly middle-aged man). Asterix is not exactly sexless but a gag like that would never get into the main stories.
The Revolutionary War hero Tomahawk received a pretty good Vertigo reimagining in Vertigo Visions: Tomahawk.
A lot of Disney comics are often this. The Little Mermaid and The Lion King have quite a few dark examples. For example, The Little Mermaid comic "Serpent Teen" has Ariel meeting a race called the Moray. They thought that mermaids wee a myth and consider them dangerous. The princess ends up keeping Ariel as a pet, and when Ariel's older sister Aquata arrives to help her she's almost eaten by a monster. Ariel ends up revealing she's a princess and is held hostage. The king of the Moray wants to kill all the merpeople however when Triton appears he destroys a lot of their town to get his daughters back.
The comics is this to the cartoon. In the cartoon the main characters nearly died dozens of times but always escape without a scratch. The comics are aimed at a slightly older audience than the cartoons were, so they get away with light curses like "hell" and characters being shown injured. Clash nearly kills Jem in an early issue but Aja pushes her out of the way. Aja ends up with cuts and bruises, as does Jerrica. A few issues later Pizzazz gets into a violent car crash which leaves her unable to be in her band for a while.
Played comedically in the second arc. In the "Dark Jem" arc Jerrica and her sisters get brainwashed by Synergy. They start dressing in darker toned outfits, start wearing black makeup, begin talking in monotone, act dismissive about everything, and generally act like stereotypical goths. Their new moody attitudes clash heavily with their typical, sweet and energetic ones.
This is parodied in the "Comic Book Carnage" issue of Hack/Slash, set at a comic fan convention. A new comics company is depicted reviving an old comic called Wunderkind (a blatant Captain Ersatz for Captain Marvel) in a ridiculously over-the-top grimdark manner, whereupon a pair of Loony Fans are so outraged that they start murdering the comic's creators (who are real-world writers and artists who were pals of the comic's writer Tim Seeley and didn't mind getting bloodily slaughtered on paper).
The Flintstones, while still basically The Flintstones, features a lot more adult humor and storylines than what would be allowed in the 1960s cartoon. For example, Fred Flintstone and Barney Rubble are Shell Shocked Veterans, and in one issue Fred and Wilma are ostracized for practicing monogamy. Despite the more adult themes, the comic has a lot of heart, such as the topic of gay marriages (non-breeding pairs aided others in Fred's tribe).
Scooby Apocalypse is a much darker take on Scooby-Doo than what was done before by having Mystery Inc. fighting against real monsters in a post-apocalyptic setting.
Even though Billy Batson and the Magic of Shazam was generally an all-ages, Lighter and Softer take on Captain Marvel and the Marvel Family, its version of Freddy Freeman was darker than any other continuity's. Instead of suffering from partial paralysis, he's a complete paraplegic; and since Freddy's spine was broken by a building that Captain Marvel imploded, he hates Billy and Mary, and blames them for his injuries. This is a far cry from the original Freddy, whose spine was broken by Captain Nazi, who idolized Captain Marvel for saving his life, and who generally managed to have a fairly upbeat attitude despite his troubles.
The Marvel Comics two-issue miniseres by Warren Ellis entitled Ruins, a darker take on Marvels where everything in the Marvel Universe has gone horribly wrong and the few characters who aren't horrifically disfigured or horribly killed by the accidents that gave them their powers in the regular Marvel Universe are corrupt and vile. Notable examples include Bruce Banner becoming a barely living mass of tumors instead of the Hulk, Charles Francis Xavier becoming a corrupt president who imprisons mutants and mutilates them to keep their powers in check (e.g. blinding Cyclops to disable his optic blasts and de-limbing Quicksilver to prevent him from using his super speed), and Peter Parker's radioactive spider bite covering his body with a terminal web-like rash.