Every character listed is based off the history before Black September (the acquisition of Malibu Comics by Marvel).
- Rex Mundi is possibly the greatest villain the Ultraverse has ever known. Once a caveman changed by alien visitors into the first Ultra, Mundi proceeded to gain his freedom and tested his powers by slaughtering innocents left and right. Desiring a perfect "utopia" to reign over, Mundi created a perfect mate who would eventually become known as Regina who broke from him due to the evil of his plans. Disgusted by the appearance of other Ultras, whom he views as inferior, Mundi would create NM-E, a mechanical monster that hunts down and kills Ultras along with any innocents nearby. Over the course of centuries, Mundi has been responsible for the deaths of countless Ultras and innocents, while creating a web of criminal empires that foster more death and misery. Forming a deep enmity with the Ultra Hardcase, Mundi eventually reveals his true plans: to exterminate the Ultras to the last before he completely destroys the minds of all the billions of innocents on earth to serve him in his utopia. A tyrant with delusions of godhod, Mundi stands as one of the greatest threats ever faced by the Ultras.
- Lord Pumpkin, debuting in Sludge but eventually becoming one of the most recurring and wicked villains to come out of the Ultraverse, started life as a mere magical construct for a bratty prince intended as his friend, only to horribly murder the prince once he tired of his abuse, kill his parents, and transform their fair kingdom into a pit of sorrow where all who stood against him were killed. Pumpkin, on Earth, becomes a drug lord to begin his intended conquest, massacring his rivals peddling "Zuke" which leads to countless innocents—children included—Driven to Madness and many others killed; later violently killing, resurrecting, and mutating the clowns and audience of a circus he ends up in after his first death and keeping them bound as agonized freaks. Killed again, Pumpkin rebirths by slowly and painfully taking over the body of his only friend before using his new position as servant of the god Argus to try and take over the Godwheel itself. Failing this and once again defeated, Pumpkin restores himself by manipulating a lonely little girl into freeing him from his bonds, before slaughtering her parents and brutally crushing the girl's neck while cackling over his betrayal. Even shortly before his final moments, Pumpkin still plots the death of all those who stood against him and their families while resuming his throne. Even with numerous excuses and reasons offered for his endlessly vile ways, Pumpkin undermines and subverts all of them, ultimately standing as nothing more than an unrepentant sadist followed by death wherever he goes.
- Firearm: Rafferty is a suave, gleefully smug psychopath with a love for every form of murder and a predilection for targeting Ultras. Having started his criminal career as a child by gunning down his own parents and framing his neighbor, Rafferty grows up to become a prolific murderer of Ultras, killing them off one by one in a sick game in which he hopes to claim hundreds of their lives. Viciously murdering dozens of Ultras, be they vigilantes getting their start, elderly folk just living in peace, or children hoping to one day become heroes, Rafferty notably murders several people just to use their blood as directions; tricks his Arch-Enemy Firearm into killing an Ultra for him; and regularly uses dozens of his hired guns as cannon fodder. In his worst scheme yet, Rafferty leads an assault on a church, killing dozens of people and revealing his plan to kill an infant girl whose power of healing has been used to save the lives of numerous people. An utterly despicable monster who stands out even among the various god-like or Ultra villains, Rafferty is one of the poorest excuses of a human in the Ultraverse.
- Mantra: Lord Boneyard, Arch-Enemy of Lukasz/Mantra and brother of her mentor Archimage, is a lecherous tyrant with a legacy of pain behind him. Even before the main plot, Boneyard has long ruled his dimension as a despot with rebels killed and slavery of all sorts promoted throughout the realm, having already murdered Lukasz's wife and brainwashed Archimage's wives into becoming servile concubines he rapes at his own whim. Eventually butchering Lukasz's allies and kidnapping Archimage, Boneyard exults when Lukasz is transferred into a female body and resolves to turn her into breeding stock, solely to father children to fatally harvest magical energies from. Throughout the series, Boneyard routinely butchers dozens of his own people to power his scrying pool; tries to eat a toddler on a whim; and redirects the demons attacking his realm to Earth to let them ravage it, constantly attacking Mantra and all her friends while viciously punishing his own minions and all else who stand against him. In his cruelest scheme, Boneyard, after having tortured Archimage to a battered wreck over a course of months, sets him up to be publicly executed to draw out Mantra—before casting an illusion and tricking her into killing Archimage with a monstrous smile on his face. The architect of unending misery and spite throughout the series, Boneyard is loathed and feared by every soul who knows his name and deeds.
- Anton Lone is the father of Nicholas Loneaka Solitaire—and the most personal villain the vigilante faces. Having clawed his way to power in the crime world by killing anyone in his way, Anton pays for and indulges in various human trafficking, drug, and arms rings while funding his bigger schemes of such things as bloody coups and government takeovers in third world countries. After failing to nuke all of Los Angeles to turn it into prime real estate, Anton begins cloning an army of Ultras to use in dominating America after he betrays the rest of humanity to be destroyed by the Fire People, and guns down his loyal Dragon to spare himself humiliation. When confronted by Solitaire, Anton remorselessly tries to murder his own son, boasting all the way the fact that he had actually murdered Solitaire's mother and Anton's own wife years ago.
- King Pleasure, from the first issue, is a vicious human trafficker and crime lord who specializes in people "easily missed" for his business. A depraved sadist on his own time, Pleasure keeps a harem of personal slaves for him to torture and rape all to slake his sense of satisfaction, treating his slaves and even his own men as easily-replaced property and even inducting a young boy to serve his tastes as well. Finally confronted by Solitaire, Pleasure tries to flee his "Pleasure Dome" as it burns down, leaving his chained-up slaves to burn alive and gleefully spouting his insurance doesn't cover human lives. Even as an incredibly minor villain, King Pleasure still stands out as a pedophilic, self-indulgent monster thoroughly drained of any decent qualities.
- The Degenerate, from issues 7 through 9, is a twisted arsonist, obsessed with proving the true "ugliness" of society. To this end, he targets beautiful artworks, historical sites and famous people, murdering large amounts of innocents with the fires he sets. When Solitaire is on his trail, he tracks the Degenerate to an orchestra performance where the Degenerate incinerates the conductor and attempts to burn down everyone in attendance. Escaping justice, the Degenerate casually murders a father in front of his daughter before attempting his most audacious and monstrous plan yet: kidnapping or buying dozens of children, the Degenerate takes them to a famous art museum, locked in barrels, where he intends to burn them alive as his greatest statement, taking only one to be his apprentice when the child proves more sadistic than the rest. Obsessed with proving every human being is nothing more than "slime", the Degenerate delights in every fire he sets and every innocent life he destroys.