- John Dread is the leader of the terrorist cell "DREAD", an organization dedicated to world domination no matter the body count involved. Dread controls his organization with a cold ruthlessness, never hesitating to order the deaths of millions of people at a time if it serves his goals, and employs the likes of madmen Psycho and Vitriol in his plans. Blacking out Paris to blackmail it and the rest of the world once the death toll rises, trying to nuke cities to ignite world wars, and nearly destroying the United Nations headquarters being just some of his atrocities, Dread hones his hatred in on Max Steel after the hero scars his face, and takes Max's best friend hostage for an exchange, then tries to kill his friend anyway. In his final scheme, Dread attempts to wipe out the entire city of Geneva and frame N-Tek for it as revenge against the organization for interfering in his plans one too many times. The root of many of Max Steel's foes, John Dread didn't have the personal animosity with Max that Psycho did, but nonetheless was just as bad as his more psychopathic Dragon.
- The appropriately-named Psycho is Max Steel's Arch-Enemy and a grinning madman with death and destruction always on his mind. Serving the terrorist organization DREAD for the money and chance to indulge in his sadistic desires, Psycho routinely goes above and beyond his orders to ensure as many casualties as possible and regularly tries to slaughter thousands of innocent people, from freezing them in an icy blaze to unleashing a bioplague and proclaiming he has "six billion hostages" with it. Having a personal hatred for Max Steel, who he created when he tried to murder a defenseless boy with nanoprobes, Psycho tries to torture him to death, dissect him, and takes every opportunity available to attempt to wipe out the hero's loved ones and even entire hometown. Psycho has no true loyalty to DREAD or his own partners, betraying John Dread when it suits him and trying to kill his own accomplices when they outlive their usefulness, notably executing Bio-Constrictor while trying to turn every human in the world into his mutated slave, wanting to rule the planet alone. Max Steel faced many villains, but Psycho was his most recurring, most despicable, and most loathed enemy.
- Miles Dredd, the founder of Trans Human Industries is Max Steel's most personal, hated foe, with a hammy personality and ambition that eclipses all over villains. Coming to rely on TURBO Energy for sustenance after betraying and trying to murder his heroic partner, Jim McGrath, Dredd tries time and again to murder the man's son Max McGrath by draining him of his TURBO Energy, notably trying to channel TURBO through thousands of people and drain them of their lives and luring Max out by threatening to kill dozens of his classmates. Eventually betraying the entire Earth to the planet destroyer Makino after endangering thousands of people multiple times, Dredd first hopes to become a general in Makino's forces before scheming to betray the warlord himself and go on a galaxy-wide conquest, uncaring that the Earth will be destroyed due to his betrayal. After the end of the series proper, Dredd returns in the Morphos duology, creating the tortured abomination Morphos who he abuses and manipulates into destroying Max, after which he murders the childlike Morphos, denouncing the creature as "nothing" and bragging that he never cared for it, or anyone but himself.
- Makino is a sadistic intergalactic warlord who destroys and consumes entire planets to "absorb and expand" his growing Ultralink armada. An AI who murdered his creator, Makino has laid waste to planets across the universe for decades, capturing and using Jim McGrath as a living battery for several years and he continued his conquest. During his invasion of Earth, Makino tortures the Uktralink Steel to learn how he turned against him, abuses his own loyal soldiers, and draws out his foes' deaths for his own glee, hoping to wipe out the planet while tormenting Max that his family and friends will die. Though seemingly beaten, Makino returns in Wrath of Makino, possessing Max's body, mind raping him, and revealing his plans to annihilate the entire Earth out of spite for being beaten, showcasing once and for all that Makino is an independent, actively evil creature capable of ignoring whatever programming his creator gave to him.
- Team Turbo & Team Turbo: Fusion-Tek: Professor Mortum is perhaps the most viscerally horrifying foe that Max Steel has ever faced, despite his sick sense of humor. Once a plain mortal man obsessed with immortality, Mortum invades N-Tek and tortures its hundreds of agents over the course of several hours to get his hands on the reality-altering Connect-Tek device so as to become a god. After being defeated and killed, Mortum uses the Connect-Tek to rise from the grave as a "techno zombie", beginning to feed on the minds of first his own minions, then all citizens of Copper Canyon, turning them into his mindless, monstrous slaves. Attempting to add his own nephew to his victim count, Mortum kills a variety of soldiers that try to combat him before turning the entire world into a wasteland that slowly turns the rest of humankind into his slaves, with Mortum giddily forcing Max Steel to watch as his friends and loved ones are turned and brags that he's going to rule over the apocalyptic Earth as supreme for all eternity.
- Turbo-Charged & Turbo-Warriors: Dr. Prometheus Halifax, known almost solely as Terrorax, is a high-ranking member of the cult known as Nexus, whose goal is ultimate dominion over the world. After stealing the powers of Max Steel and transforming it into "Terror Energy", Terrorax reveals to the Nexus High Command his plan to wipe out all technology across the globe except that of Nexus, plunging humankind into an extinction-level event where only those who swear fealty to Nexus will survive. Though thwarted for a time, Terrorax devises a new plan to use Terror Energy as a weapon of mass destruction, travelling to cities and destroying them one by one until the world surrenders to his demands, and, when in his final fuel with Max Steel, Terrorax reveals his dream of bringing mass death and chaos to the entire planet before betraying his Nexus masters, wanting nothing more than to rule over the ashes of humanity as a god.
- Covert Missions: Dawn is an Evilutionary Biologist who believes that humankind has grown weak and needs to evolve under her guiding hand. Orchestrating the kidnapping of Jefferson Smith, Dawn performs a variety of experiments on people to turn them into monstrous, zombie-like abominations that she seeks to transform all of humanity into, leaving her experiments and own soldiers to die when she flees Max Steel and sets her base to self-destruct. Dawn first tries to launch a missile to wipe out an entire city and transform its population into her zombies, then reveals her newest plan to use a gaseous dispersal plan with an air blimp, hoping to move from city to city until every human is a writhing, twisted creature bent to her will.
- 2016 film: Miles Edwards is a sociopathic Mad Scientist obsessed with harnessing the alien power of turbo energy. To this end, Miles betrayed the Earth defense force he was part of, N-Tek, to the evil Ultralink aliens, leading to the deaths of at least 5 of his former partners. In exchange for allying with the Ultralinks, Miles was granted the capability to betray his former best friend Jim McGrath, who constantly produced turbo energy due to his alien biology, and tried to drain him of the turbo energy, leading to the man's agonizing death. Years later, once learning that Jim's teenage son, Max, has begun giving off turbo as well, Miles sics an Ultralink on the boy, nearly killing innocents in the process, and, after failing to trick the boy into giving up his turbo, Miles settles for absorbing the Energy directly into himself, hoping to kill the boy in the same painful way as his father, while brutally murdering numerous N-Tek soldiers who attempt to save Max. Miles is fully aware that the Ultralinks are world destroyers and will invade Earth once the turbo energy is contained by him, but doesn't care one bit, showing no concern for any life or person except the turbo energy he is so obsessed with.