Complete Monster/DC Films

Like Marvel, DC has made a plethora of films throughout the years, with many of them having truly horrible and vile villains as per DC's line-up of baddies.

DC Extended Universe

 * General Erich Ludendorff in Wonder Woman (2017 film) demonstrates that even in a world of gods and monsters, some humans can be the most evil beings around. A ruthless German general in World War I who believes in continuing the war, Ludendorff executes a man simply for complaining supplies are low and encourages the inhumane research of Isabelle "Dr. Poison" Maru, testing her gasses on live subjects. When he encounters his high command who wish to sign an armistice, Ludendorff gasses them as well, but throws in a single gas mask, well aware it will do nothing to stop the gas. Ludendorff later tests the gas even further on a civilian village and when he engages Diana herself in a battle to the death, he is in the process of having the gas loaded into a plane to subject all of London to a horrible death.
 * In Justice League (2017 film), Apokolips' military leader, Steppenwolf, had burned countless worlds by the time he came to Earth, killing millions and raising them as monstrous Parademons, before he tasted defeat. Returning thousands of years later, Steppenwolf seeks to recover the lost Mother Boxes to enact his plan of wiping out life on Earth to turn it into a blasted hellscape like his own homeworld, hoping to offer Earth to his master Darkseid and end his exile. Massacring the Amazon warriors guarding their Mother Box and later doing the same to the Atlanteans, Steppenwolf captures humans who may know of the third Mother Box, killing them when they don't have the info he wants and preparing to torture another until he talks. When the newly formed Justice League moves to stop him, Steppenwolf puts his plan into motion and unleashes his forces on civilians, intending to annihilate all life on Earth to erase the memory of his past failure.
 * Harley Quinn: Birds of Preys (2019 film) has the Big Bad and his Dragon as examples.
 * Roman Sionis AKA Black Mask is a powerful crime lord in Gotham City who seeks to gain a diamond containing the code to the now dead Bertinellis' fortune and use its wealth to spread his influence and power throughout Gotham. While portrayed as a gentleman and businessman, Sionis is a childish psychopath and narcissist so obsessed with attention and image that he has a woman stripped and forced to dance simply for laughing in his presence. Sionis also loves Cold-Blooded Torture and gruesome deaths, with one example being when he had Victor Zsasc cut the faces off a family, including their young daughter, when after agreeing to spare her, changes his mind because the girl's crying repulses him. Discovering the pickpocket Cassandra Cain has the diamond, Sionis puts a hit on the girl and sends his followers to kill Harley Quinn and the Birds of Prey when he's betrayed.
 * Victor Zsasc is Sionis' right hand man and a Serial Killer who carves tally marks on his body for each person he's killed. Years ago, Zsasc was one of the men who gunned down the Bertinellis under Sionis' orders, leading to the young Helena Bertinelli being orphaned and trained into becoming the assassin known as Huntress. Zsasc personally tortures and kills Sionis' enemies in extremely brutal manners, such as the aforementioned family above that he cut the faces off and led to bleed to death. Discovering Sionis' driver Laurel Lance AKA Black Canary is a traitor and finding out Cassandra Cain swallowed the diamond, Zsasc forces her to prove her loyalty by cutting open Cassandra to retrieve the diamond, and also drugs Harley Quinn and attempts to add her tally to his list.

Non-DCEU

 * In Superman Returns, Lex Luthor (now portrayed by Kevin Spacey, who's played many Complete Monsters before and since) is more bitter and notably grimmer after being humiliated by Superman, and completely loses any comedic qualities he had in the original Superman films. Having conned an elderly widow into marrying him, Luthor used her money after she died to re-group, form a new gang, and break into Superman's Fortress of Solitude where he stole several Kryptonian crystals and soon learned that he could turn them into enormous landmasses. His mind still focused on real estate and defeating a newly-returned Superman once and for all, he puts his henchwoman Kitty's life in danger by cutting the breaks to her car in order to distract Superman so he can spirit away a hunk of Kryptonite from a museum, with Kitty having not been told in advance. Soon afterwards, he takes Lois Lane and her young son as his hostages on his boat, revealing to them that he will turn the Kryptonite into a humongous landmass and cause it to displace other continental landmasses, which would kill billions of people while he would charge the survivors huge amounts of money to live on "Lexland". The worst part is that like with his smaller-scale plan in the first movie, he knows full well of the consequences, but doesn't care as long as he gets to make money and boost his ego. When Superman tries to stop him and gets de-powered by the Kryptonite landmass, Lex doesn't just try to kill Superman, he slowly and agonizingly tortures Superman by beating him to a pulp as payback for getting him stuck in jail for a few years. He even lets his henchmen get in on the fun before stabbing Superman with a piece of Kryptonite and leaving him to drown in the sea below. It's worth noting that Kitty is so disgusted by him that when his plans have been foiled yet again, she disposes of his future Lexland crystals so he can't repeat his plan again. He and Kitty are last scene stranded on a desert island, with Lex telling Kitty he would trade "every ounce of her blood" for a quart of gasoline for his helicopter, and then silently contemplating killing and eating Kitty' pet dog for food rations. A true self-centered egomaniac to the core, Lex will stomp on anyone, even his own employees in order to get what he wants and is reviled by pretty much anyone who has the misfortune to interact with him.
 * Though Jack Napier/The Joker from Batman may not have been quite so gritty in his approach as other versions of the character, the sheer scope of his reign of terror puts him on more or less the same level as his counterpart in The Dark Knight. Even before his transformation, Jack Napier was outright horrible: he was the one who murdered Bruce Wayne's parents, and if his accomplice hadn't yelled at him to get out of there, it's very likely the psycho would have killed young Bruce as well. From that to present day. For starters, he intends to poison all the Gothamites with Smylex Gas for no other reason than his own amusement, has three mob bosses killed (with him even joking about their deaths, at least one of which qualified under Nightmare Fuel, where he electrocutes him with enough voltage to turn him into a charred skeleton after claiming that shaking his hand will be the end of it if he refuses to agree with the Joker). He also horrifically disfigures Alicia Hunt and was also implied to have thrown her off a building later on in the film under the guise of suicide to free himself for Vicki Vale ("You can't make an omelet without breaking some eggs."). Gasses an art gallery full of people to death just to have some "alone time" with Vicki Vale and puts the components of Smylex into different cosmetics to cause random city-wide deaths just to make the people panic. He even cold-bloodedly guns down his best and only friend, Bob the Goon, simply to vent his anger over Batman ruining the above attempt to gas everyone at the parade.
 * The Joker from The Dark Knight Saga manages to be both a Complete Monster AND a Magnificent Bastard. At the start of the film, he has several of his minions commit what seems to be your standard bank robbery...until you realize that he also had his minions kill each other off to keep most of the money for themselves after their accomplices did their job, also disguising himself as one of their comrades. Right after that, he kills the Bus Driver (who apparently wasn't even in on that part of the plan), leaving himself with all the money. Even the Bank Manager, implied to be part of the Mob, is quite horrified at the complete decadence of this criminal behavior, remarking that most criminals before them at least had honor and respect for their comrades. Then, the Joker starts exploiting the Mob’s desire to be rid of Batman, casually murdering henchmen, politicians, and police to force Batman to unmask himself. He explicitly states that this is just an excuse. Despite implying at first that he wants payment for his services from the mob, he doesn't care one bit for money, even going so far as to burn his half of the Mob's money that he earned by retrieving it, causing even the Chechen mafioso to be frightened at the implications of this, thus making it quite clear that the Joker most likely instigated the backstab-chain earlier solely for the amusement of watching his thugs kill each other for money. Even the Mob finds this a tad overkill. All the while, the Joker states how he’s simply out to be give Gotham a “better class of criminal”. This being the Joker, he doesn’t stop there; he also makes the accountant attempting to unmask Batman a target, blows up a hospital, The Joker's entire goal is really to show that anyone and everyone can and will become a Complete Monster if they're pushed far enough (or even if they are given the chance).
 * Quentin Turnbull of Jonah Hex was once a high-ranking Confederate general who, after the events of Gettysburg, decided to show how "weak" the Union was by ordering entire hospitals and schools annihilated, and this led one of Turnbull's own soldiers, Jonah Hex, to betray him, kill his son in self-defense, then turn him over to the Union. Escaping custody, Turnbull tracks down Hex and forces him to watch as he has his Dragon, Burke, burn the man's wife and child son alive, befire branding Hex's face and leaving him to die. Spending the next years creating a superweapon, Turnbull hijacks a train shipment after having the occupants killed, and uses the contents of the shipment to finish his weapon, then wipes out an entire town and it's hundreds of residents to test it. Turnbull then plans to use his weapon to wipe out Washington, D.C. during the Independence Day celebration, killing the thousands of innocents attending, along with the President of the United States. Though at first seeming to genuinely care for his dead son, Quentin Turnbull quickly shed that aspect of his personality, showing that all he cared for was the complete annihilation of the United States government, no matter how many innocents had to die in the process.
 * The aforementioned Burke is the psychotic Dragon of Turnbull, and matches his boss's emotionless cruelty with sheer psychopathic sadism. Assisting Turnbull in all of his crimes, Burke personally, and happily, burns Jonah Hex's wife and son alive, then holds Hex in place to be branded by Turnbull and left for dead. Fully aware, and approving, of Turnbull's plans to use his superweapon to wipe out thousands of innocents, Burke blows up an entire train to obtain parts for said superweapon, killing the dozens of soldiers, citizens, and children on board, and later massacres the population of a small town to acquire the ammunition for Turnbull's superweapon. Kidnapping Hex's Love Interest to use as a hostage, Burke takes sadistic glee in smacking her around and threatening innocents with death for kicks, and regularly taunts Jonah about his family's deaths. Dying while laughing at Hex's misfortune, Burke was a homicidal lunatic who seemed to only work with Turnbull to satisfy his lust for sadism and mass murder.