Checked for an update to your favourite webcomic, and holy balls what did that guyjust do? It could happen any day now...
Advisor Toh in Blade of Toshubi enjoys torturing and breaking women. He also has a room filled with the tails of the people he has killed (including his women) that he occasionally stuffs his women into for extended periods, sometimes for punishment, but sometimes For the Evulz.
Dead Of Summer gives us Alan Stone. In flashbacks, it's revealed that he subjected zoo animals to hideous experiments, already giving him quite a few negative points. After beating the tar out of a sympathetic character and kicking him and the main character out into the dangerous, zombie-ridden city, he finds out his wife has been working on a cure for zombiism by testing it on a monkey she adored. His reaction? TEARING OUT THE ELECTRODES TO ITS BRAIN.Then he injects himself with the 'cure', turning into a literal monster. And then he injects his wife with it, turning her into a zombie. And his wife was pregnant. After all that, he injects the remaining zoo animals with it to build an army of the undead.
The Infernomancer (known by some as TIM) from Dominic Deegan. Even by the standards of a demonically empowered murderer (yes, there are more than one of these in the comic), TIM is a sick piece of work. In an early story arc, he tried to find the headmaster of the local magic academy (Dominic's mother) by attacking the school and slaughtering students until one of them coughed up her location. Unbelievably, he topped himself after becoming the servant of an Eldritch Abomination — after escaping limbo, he celebrated his freedom by massacring random places of worship. Then he wiped out a village for kicks — that Dominic's brother was also there was just a bonus to TIM.
In Everyday Heroes, Wrecking Paul appears to be just a typical Big Guy, until we find out that he is a serial killer. He specifically chooses locations where women will be present and always hires female sidekicks so that, if his regular target isn't available, he can turn on his own teammate.
Legune The Alchemist from Evon is the Resident Mad Scientist for The Cabal. The first thing we see him do is create a couple of homuncului to track down the title character, slaughtering a team of Cabal mercenaries sent by another Cabal member to do the same thing. The second thing we see Legune do is have Evon stripped naked and Strapped to an Operating Table, where he proceeds to violate Evon in the process of "procuring" biological samples from her. Then he decides that won't do and attempts to rape her outright, only being stopped by his patron, Maximus (but only because said rape might interfere with Maximus' own plans for her). We then see that Legune used those samples he took to create a clone of Evon. A clone which is physically and magically stronger than Evon, but since she lacks Evon's Super Empowering factor, she's deemed useless to The Cabal and turned over to Legune to do what he will with her. "What he will" turns out to be forcing her to give him oral sex while taunting her with imminent destruction if he doesn't please him.
Emperor Nicholas the Puissant of General Protection Fault, who has conquered the world in an alternate dimension. He kills people who fail him, tortures Nega-Ki to ensure his counterpart's obedience, then threatens to torture prisoners to death in front of him if he wastes time, and it is ultimately revealed that he doesn't want Project Velociraptor so that he can win the war with the aliens laying waste to Earth, but so he can escape and re-establish himself elsewhere.
In Girl Genius, Lucrezia/The Other qualifies for this trope on the basis of enslaving and slaughtering many thousands of innocent people, betraying the world's greatest heroes, and being the worst mother ever - killing her own son, using her own daughter for a Grand Theft Me, and then plotting to kill said daughter when that plan goes badly awry. She shows no remorse or sympathy for anyone other than herself, whether they are a victim, an innocent bystander, or one of her own loyal minions.
Dellyn Goblinslayer, ranger and captain of Brassmoon city's elite guard. Highly sadistic Torture Technician and Fantastic Racist whose hobby was capturing live monsters, then vivisecting them in order to learn their weaknesses. He also had a Yuan-Ti slave named Kin, who he raped and beat on a regular basis. Kin's revenge on him was anything but pretty.
Mryorg the Ogre, who appears in the backstory of The Axe of Prissan. Having had dealings with demons since a young age, he forced a captive demon to carve a rune on his chest. The rune gave him the ability to communicate with demons and make occasional journeys into the first layer of hell; in return, these journeys burnt away his ability to take pleasure in anything except the suffering of others. Learning of the Axe of Prissan, an artifact used to bind a powerful demon, he sought it out solely so he could release the demon from its prison; when he aquired it, he went on a rampage and butchered many good creatures, in a time that paladins call the 'Time of Dark Fire'. Eventually, he gave the Axe to a paladin, not out of any kind of remorse, but simply because he decided that knowing the demon lord was suffering from being imprisoned gave him more satisfaction than the suffering the demon would unleash by gaining freedom.
Kore is a dwarf Paladin who makes Fantastic Racism his own personal crusade. He indiscriminately slaughters any members of traditional Always Chaotic Evil "monster" races (goblins, orcs, ogres, etc.) he meets on a one-man genocidal rampage...in a world where it's clear for readers only demons and undead can be considered such. He doesn't even spare defenseless elders and those begging for mercy (also their women and children, but that last part's Offstage Villainy). When confronted with a small child from his own race (dwarf) who was literally Raised by Orcs - but whose foster father was a kind man, and raised him to be a decent person who wouldn't be afflicted by the Fantastic Racism endemic to the setting - and whose said foster father begged him to spare with his dying breath, he monologues that even if the boy's been with the orc for about a year he's been hopelessly tainted (keep in mind this is a Dungeons & Dragons-based 'verse, where dwarves are the human equivalent of 15 at 60, meaning even a 7-8-years-old-looking kid would probably have at least about three decades of time to be "purified") and butchers the kid like any of the other humanoids he just massacred. When Chief attempts a You Shall Not Pass on Kore (who utterly outclasses him) so the rest of the goblin party can escape, Kore chooses the vile utilitarian path - after downing Chief, he heals him so he doesn't die... then submits him to Cold-Blooded Torture so his screams of pain will lure back the rest of the group. This also shows him to be a hypocrite, as he's basically using his prey's basic moral decency against them while still considering them irredeemable Always Chaotic Evil scum. He has had zero Freudian Excuse revealed and there is a serious Fridge Horror of realizing that either he never used his Detect Evil, or worse that he routinely ignores what it reveals (that his prey aren't all evil by a longshot), which dovetails his twisted world view that anyone associating with what he considers evil monsters are tainted and worthy of nothing but pitiless extermination, no rehabilitation possible (like that poor dwarf kid mentioned earlier).
In The Powerpuff Girls, Him is actually already pretty bad, but in Grim Tales, it gets ridiculous. The fact that when he cut off his own daughter's hands so that he could replace them with claws was the least of his crimes is an indicator. He also tortured said girl with every horrible experience he knew of in the ultimate Break the Cutie. He had Minimandy nearly kill her brother with More Than Mind Control, afterscrewing with their heads. When Him got betrayed by Her, he got really mad, which is understandable. But he later said he's mad not because of what she did but why she did it - to save her friend, telling her that if she did it for completely selfish reason, he would actually be proud of her, but the Power of Friendship is just disgusting to him. Could see that coming, since he's Satan. Now that he's free from the shackles of cartoon censorship, do you honestly expect himto notexploithis creative freedom?!
From Homestuck, we have Caliborn, better known by his title, Lord English. He killed his own sister through proxy, enslaved the Handmaid after his awakening, murdered the author out of spite in-story, and permanently killed hundreds of largely harmless doomed timeline characters. What's worse is that he essentially has no real motivation to do what he does. Power? He's already got plenty of that. Galactic domination? He'd rather destroy it all himself. If what's been said about him indicates anything, it's that he's just doing it to amuse himself, and to completely obliterate his sister and all that she loved.
The apple didn't fall far from the tree, apparently. Caliborn's ancestor destroyed hundreds of planets and killed millions unprovoked - and, like his son, for his own amusement. The cherry on top is that if Aranea's narration is to be believed, Caliborn is even worse.
Natalie Geln from Khaos Komix is a homophobic bitch. She attacks two Transgendered (Charlie, a MTF, and Tom, a FTM) students outside the school, cuts Charlie's hair, taking half of her ear-lobe with it, and orders two boys to rape Tom. She then gives a long speech about how she doesn't want any freaks in "her" school, and they should "Do the world a favour and kill themselves." The worst part? Not even that shit like that happens in real life or that anyone could easily become like her were they to allow certain biases to grow to monstrous proportions. She wins.
The Seer of Kid Radd is essentially a virus that didn't go off on the day it was scheduled to because he realized that humanity would survive. He spends the entirety of the comic finding a way to get a sprite body, then a physical body, so he could kill everybody in both worlds. The kicker? He didn't need to do any of this. He could easily kill both populations at any point, but wants to be there physically so he can see his victims cower in fear of him before he slaughters them. Then, once he was done with Earth, he planned to search the galaxy for other forms of life just so he could go on killing for eons.
Mordecai Heller, the Obsessive-Compulsivehitman of Lackadaisy. His OCD arguably makes him even more of a monster - he once killed his getaway driver for sneezing too much. He launched into a terrifying tirade against a man he was going to kill because his position in the backseat upset the symmetrical balance of the car. Mitzi mentions that, when the Marigold gang gave him a better job offer than the one he had, he kneecapped Viktor, his partner of several years, on his way out the door.Perhaps worst of all, certain lines of dialogue indicate that he may have had a hand in the death of Atlus May, his previous boss and Mitzi's husband.Word of God has actually stated that Mordecai has no morals whatsoever.
In Mind Mistress, Lolerei's grandfather (who appears only in retrospections) hired Les Kidman, a pedophile and murderer, as a part of a plan in which he was supposed to kill her, because Lolerei is mentally challenged and her grandfather considered it a disgrace to the family name.
Mob Ties has Bengal, who is a rapist, murderer, and freakin' god of undeath confined in a human form. Among his many sins, he has raped Mika, who was 13-14 at the time, murdered Mika's best friend Kyoko, and then destroying the one object that might have undone that murder. He also killed Santa Claus.
Bram from Nosfera made dozens of women into his mind-controled sex slaves and planned to do it to his own wife, the title character
Cyndi from Penny and Aggie. A manipulative sociopath who almost gets off on driving people to suicide. In a really creepy and incriminating file on her laptop, she documented how fun and easy it is to dig a hole into someone's psyche and widen it. She brags about nearly driving Michelle into starving herself to death and she had plans to destroy Daphne and Sara's relationship in the hopes of getting one or both of them to commit suicide. In the same strip this was all revealed, she successfully goaded Charlotte into slitting her own throat by using her Mommy Issues against her. Seeing someone bleed out in front of her thanks to her words puts a grin on Cyndi's face. What's even more damning is that both her biggest "success" so far AND her next intended victim, who she merely considers "practice" (Meg), are erstwhile members of her own clique from the "Popsicle War" arc.
Ditto from Pokeslaughter is a sarcastic, murdering, sociopathic rapist who started all the events in this comic in a failed attempt to take over the world.
Susan from Sire. You might be inclined to think of her cruelty to Anna as the frustrations as a lonely child. That is, until she savagely beats in the head of the only person who cared about her, simply because he didn't shower her with enough attention. After this, she pins the rap on Anna, laughs off her suicide attempt, snaps the neck of her lawyer, smuggles herself and Anna into another country, and leaves her at the hands of some unsavoury types. And while she's doing all this, she coerces Anna into thinking that it was all her fault.
Avogadro Pompey stands out as a Complete Monster even compared to the Jerk Ass cast of Something Positive: he kept Pepito as a sex slave, psychologically and physically abused his nephew, and set Kharisma up to take the rap for a murder (his own, as a matter of fact) which she didn't commit.
Starfish, from Unsounded, the leader of the Red Berry Boys, a criminal gang that earns money by kidnapping people, cutting out their organs, and using the available space to transport a magical substance in their captives' bodies. The process leaves its victims drifting in and out of consciousness, all the while in a constant state of pain. Recently, Starfish has made it a priority to target children for this procedure. He does so because his buyers pay him the same amount per body, not per amount of substance in each body. By using smaller bodies he can stretch out his supply, swindling his buyers out of extra cash. What this process entails is shown in gruesome detail with Cara, a little girl who the readers see slowly dying on an operating table, having had most of her organs removed and then been abandoned by Starfish when his lair was uncovered. In addition to his rampant greed, Starfish is prone to partaking in brutal and sadistic actions simply because he can. When his mook, Ephsephin, has been gravely wounded and is begging Starfish for a doctor, Starfish merely smiles and caves in the man's skull with a whiskey bottle. He also, once better muscle comes along, betrays Quigley, an Antivillain who only signed up with Stafish so long as the captive children were set free once the job ended. Not only does Starfish renege on their deal and attempts to have Quigley killed, but he even states that Quigley’s eight-year-old son, Matty, will undergo the procedure as well. Additionally, as Starfish tries to have Quigley drowned, he forces a crying Matty to watch the whole thing.
Doctor Chu in Wayward Sons is a brilliant scientist who gets most of his results through torturous experiments on live subjects. Or, put another way, he's a professional torturer who learns a lot of useful things while on the job. Either way, he certainly enjoys what he does.