General Miles "Mayhem" Manheim is a military man. A soldier since his youthful days, he later served under Joe Colton as part of the Adventure Team. During this time, Manheim got his nickname from Colton because of his innate talent for causing disruption and chaos among enemy forces. Miles was a brilliant soldier and one of Joe's best friends.
However, Mayhem's heroic actions soon gave way to villainous intentions. Carrying a deep desire for wealth and power, Mayhem is methodical and a master manipulator. He is able to use the people around him like pawns in a game of chess. He is incredibly cold and is willing to sacrifice anyone, deeming human lives an "acceptable loss." His ultimate desire is control over the world, and he's more than happy to sell out his allies and side with whomever he must to gain what he believes he deserves.
Mayhem served as head of Project Spectrum along with Cornelius Trakker, devising technology to defend the planet, later overseeing the training of a group of operatives, including Cornelius's son Matt, that would form the Mobile Armored Strike Kommand and their rival black ops unit V.E.N.O.M. As part of V.E.N.O.M., Mayhem pilots the Switchblade vehicle and wears the "Python" Mask.
Much of Miles Manheim's past is shrouded in mystery. He grew up in a rough neighborhood in Philadelphia before enlisting in the U.S. Army. Rising through the ranks after his graduation, Miles impressed his commanders with his capabilities in espionage and black ops strategy. Manheim was also willing to sacrifice whatever he needed to, even if it resulted in "collateral damage". At one point early in his career, Manheim was captured by opposing soldiers and tortured for information. He ended up giving up the location of his allies' base, and later killed his tormentors in revenge. The experience changed Miles, and he swore to never "be weak" again.
Miles later joined the Adventure Team, where he received his infamous nickname of "Mayhem" from the team's leader: "G.I. Joe" Colton. During this time, he went on many adventures, including encountering the British agent Action Man, though he didn't find the experience very memorable.
On one of their missions, the Adventure Team responded to a distress call from the Tomb of Amtoltec in Dashur, Egypt, where they fought roboticized mummies that Garrison Kreiger had unearthed. While Stalker, Bulletman, and Atomic Man were occupied with numerous robots outside, Mayhem followed Joe into the tomb and saved his colleague when Soundwave blew out a tomb floor. They followed Soundwave further in to find Kreiger with the Talisman. Their teammates soon arrived and their continued interference annoyed Soundwave to the point that the Cybertronian violently departed the pyramid. The debris would have crushed the humans if not for Atomic Man, newly modified by the Talisman, using his powers to block the debris. In the aftermath, the Adventure Team took custody of the Talisman and handed it over to the British S.I.S.
Mayhem was present during the team's operation to rescue Dr. Emil Burkhart. While Stalker was nervous about their chances of survival against the IRON Troopers, Mayhem told him to stow the fatalism. Unfortunately, despite the best efforts of Atomic Man, the team was unable to save Burkhart.
Mayhem remained part of the team after it was renamed "Adventure Force," growing a magnificent, manly mullet in the meantime. In 1994, Adventure Force raided Garrison Kreiger's Brasnyan facility, looking for Mike Power. However, by the time they arrived, Power had (apparently) already died. However, they had another problem: the time-displaced Sgt. Savage.
After the Adventure Team was shut down and replaced by G.I. Joe, Manheim began to secretly sell weapons to multiple parties on the black market, while continuing his career in the Army, quickly advancing to become one of the youngest Generals in history. At some point post-Adventure Team, Miles and Joe Colton met up again at Dolphin's Bay, where (for unknown reasons) Miles tried to kill Joe. This left a noticeable strain on their friendship
Years later, General Manheim served as head of Project Spectrum, an effort to develop cybernetic weapons to combat the Transformers crafted by Cornelius Trakker. He became good friends with Trakker, as well as his wife Alessandra and son Matthew. However, Manheim ultimately ended up betraying Trakker and murdering him.
Manheim was present during the trial of Sylvester "Sly" Rax, who had been arrested by Lt. Christopher Lavinge. Lavinge mentioned to Manheim that Rax's skills could be useful for counter-intelligence work. Manheim agreed, and Rax was soon enlisted to the U.S. Army. Despite his quick dishonorable discharge, Manheim still saw potential in him, and recruited him to Project Spectrum.
One of the many illegal activities Manheim was involved in was betting on illegal fight club matches. His associate, Big Boa, turned him onto a fighter named Cliff Dagger. After Dagger won a fight that Manheim betted on in his favor, Manheim and Boa met to discuss his fighting prowess. While Boa commented on Dagger's lack of intelligence, his physical capabilities were exceptional. Manheim concluded that he'd make a fine addition to "the team."
Manheim used Project Spectrum as training ground for a special team of operatives, created to use their previously designed weapons and vehicles to combat Cybertronians. He personally recruited Matt Trakker to the program, having been asked by Matt's mother. Manheim oversaw each recruit's training personally, even bringing in the likes of Dr. Verstal Bender to help evaluate the best members for his team. He was disappointed to see Matt not living up to his potential, but found promise in Vanessa Warfield, bringing her into his inner circle.
As the training continued, Manheim began to show his flagrant disregard for the lives of his recruits, something that deeply troubled Matt. During their final test, Manheim used hard-light holograms to create a group of civilians the recruits were unable to rescue from an exploding train, wanting to test their reaction to failure. Bruno Sheppard.Among those incensed by this manipulation was
After Talon captured Blitzwing, a Dire Wraith posing as Joe Colton relinquished the Triple Changer into the possession of Miles, who used him to perfect the Project Spectrum vehicles. Blitzwing was also used by Manheim and Garrison Kreiger to test the destructive effects of the Talisman on Cybertronians. Manheim then met with Wraith-Colton and Scarlett to discuss the activities of the Transformers on Earth. He interjected during Colton's rant to point out Optimus Prime had come back to save them from the Decepticons and help them rebuild, but he was pretty dismissive of G.I. Joe. Colton revealed Manheim was there because Ore-13 was going critical thanks to Transformer activity and was likely to devastate the planet, and he was hoping Manheim could reverse-engineer something to help them fight from the mutilated but still conscious Blitzwing. Miles was more than happy to be given a chance to overthrow a tyrant like Optimus Prime!
After the battle between G.I. Joe and the Transformers in Portland, Oregon, Manheim sent Matt Trakker, Gloria Baker, Brad Turner, and Julio Lopez to G.I. Joe's headquarters at Governor's Island, where he introduced Scarlett to the Mobile Armored Strike Kommand! While at Governor's Island, Manheim continued his dissection of Blitzwing, keeping him alive throughout the process. When Scarlett asked him if the robot was in pain, he dismissed her concerns since it was only a machine.
Mayhem later led an attack to neutralize the Autobots Kup and Aileron in Greece. After the initial M.A.S.K. agents (including Warfield, Rax, and Sheppard) engaged the Transformers, Mayhem arrived in the Switchblade, firing on Kup. Mayhem decided that the truck was more valuable alive then dead and decided to wound him so that he could be captured. He then transformed the Switchblade to go after Aileron. She escaped, but not before Mayhem ordered Matt Trakker to jam her communications with Autobot City. After the battle, Trakker confronted Miles about the fact that Transformers weren't the mindless machines he thought, but living beings. Mayhem just responded that this was war. In war, people–and things–get hurt. When Trakker confronted Scarlett, Mayhem took the young recruit to ease his mind. Trakker tried arguing that the Cybertronians were living beings, which Manheim objected to, claiming they weren't alive, right in front of Kup. He continued on to say that all he was doing was for the Greater Good. As they talked, the base came under attack, with the M.A.S.K. vehicles being the best assets on hand. When Trakker felt unsure, Miles suggested he trusted him, like Matt's dad had, which definitely wasn't at all suspicious. As Matt left, Miles talked to Vanessa and Sly, telling them to make sure nobody found out about Kup. By the time Manheim and Trakker were in the air, the base's attacker had already managed to get to Kup and free him. Thanks to some interference from the Joes, Kup and his rescuer escaped, prompting Miles to change his priorities from "capture" to "kill". On landing, he pegged Mainframe as being responsible, only for Agent Helix to cover for him. Convening with Vanessa and Sly, Manheim suggested it was probably time for them to start packing.
The next morning, Miles received a call from Caleb Awan, the Dire Wraith leader, telling him that they were running out of time; the Wraiths were ready to move, regardless of what happened with their "other allies." Manheim reported that there was a sizable amount of Ore-13 underneath Autobot City before being interrupted by Matt. He quickly ended the call and told Matt to pack his bags. Mayhem led the M.A.S.K. team in an assault on Autobot City, where he called in his reinforcements: a squadron of flying Dire Wraiths! M.A.S.K. and the Wraiths pushed through the city’s defenses, Mayhem reveling in the fact that he will control Earth once he and his allies are victorious. However, as he gloated, the Dire Wraiths attacked the Switchblade, causing it to crash to the ground as Matt yelled at him for betraying the Earth. Mayhem countered that he knew aliens were coming, and that he planned to take any step necessary to save the world. Using the Switchblade’s Cybertronian technology, he connected to the Autobot City spacebridge and activated it, allowing his other ally, Baron Karza, to come through from Microspace. Karza then used his Enerchange ability to merge with the Wraiths, transforming into a monstrous fusion of Microspace, Cybertronian, and Dire Wraith power.
As the Karza-Wraith began laying ruin to Autobot city, Trakker accused Mayhem of creating the monster. Miles claimed that he merely revealed the inevitable result of what aliens will do to Earth and ordered Trakker to continue attacking the Transformers. After Mayday informed the Joes that the ore-13 was about to ignite, Sly Rax asked if Mayhem had a plan, which Mayhem assured he did. With Metrotitan moving away from the Ore-13 deposit, Mayhem decided to launch a final attack towards the Karza-Wraith, crashing the Switchblade into it and seemingly sacrificing himself in the process.
After the battle, Matt Trakker discovered a note (unsigned) that Mayhem left on the windshield of wrecked the Thunderhawk, saying that illusion was the ultimate weapon, and that he would see Matt soon.
Back at their base, the M.A.S.K. recruits wondered if Mayhem could really be dead. Matt speculated he wasn't and posited that he could be working with the Cybertronians to manipulate the world's defense agencies. Shortly afterwards, Bruno took the prototype Rhino out for a solo drive. However (against Mayhem's earlier warnings), he pushed it too far, resulting in the Rhino exploding. Before the Rhino was completely destroyed, Mayhem used technology the Earth Defense Command appropriated from Skywarp) teleported Bruno, Sly, and Vanessa to a secret base. Unfortunately, Bruno was badly burned in the ordeal, forcing Mayhem to replace much his with flesh with cybernetic enhancements. When Sly asked Mayhem what was going on, Vanessa revealed that M.A.S.K. was merely a front for the General's real plan: a black ops unit called V.E.N.O.M. Together, they would destroy Matt Trakker and the rest of the M.A.S.K. team!
Shortly after the "Revolution" event, the real Joe Colton (acting as the villainous "Baron Ironblood") approached Mayhem, who was casually dissecting Blitzwing, to recruit him to the Iron Ring. However, Miles was incensed that Colton did not come to him first, to which Colton simply reminded him that the last time they saw each other was Dolphin's Bay. Colton told Miles of his and Kreiger's plans for the Talisman, and that he needed someone on his team that he could trust.
With the world believing them dead, V.E.N.O.M. used their vehicles to attack high-profile military installations, framing the remaining members of M.A.S.K. in the process. With them busy running from the law, Mayhem planned to hunt down the Cybertronians on Earth and sell their technology on the black market. However, he still felt the need to take M.A.S.K. off the board, confronting them in a reconstructed Switchblade near Harrison's Cave, Barbados. As M.A.S.K. fled into the cave, V.E.N.O.M. ambushed them. With the M.A.S.K. team questioning who else could have their tech, Mayhem took of his Mask to reveal himself, along with Vanessa, Sly, and the now-cyborg Bruno, much to the shock of their former comrades. Mayhem expressed his disappointment in Matt, saying he was just a lesser version of his father, just as Matt blinded him with his Spectrum Mask and M.A.S.K. escaped out the cave. Pursuing them, he engaged Matt's Thunderhawk in aerial combat. During the fight, Matt was able to sustain damage to the Switchblade and V.E.N.O.M. was forced to retreat.
Miles Mayhem also ran a laboratory staffed by morally bankrupt scientists who had captured the Micronauts in the wake of the Revolution incident, hiring mercenary group Sirius as security. After the small adventurers had escaped, Commander Steven Klain claimed to Mayhem that their recapture was imminent.
After their first confrontation with M.A.S.K., V.E.N.O.M. traveled to Toronto, Canada, where Mayhem held an auction for several prototype Masks, based on designs originally created by Cornelius Trakker. However, M.A.S.K. had infiltrated the auction, and Matt and Gloria attacked Mayhem. Luckily, he had Bruno and Vanessa waiting in the wings to protect him. Matt cornered him, but soon Alessandra Trakker entered the room, begging her son not to kill him. This proved advantageous to Mayhem, who took Alessandra hostage with a gun to her head. Mayhem lectured Trakker on how weak he was before pulling the trigger.
However, this was just a holographic projection meant to distract Matt, allowing VENOM to capture him and Gloria. Mayhem continued to berate Trakker, explaining his plans to use the "lower-tier" Masks to become the savior of humanity after infecting everyone with Ore-13 radiation poisoning. However, Mayhem's monologue was cut short when he and Vanessa experienced electrical feedback from their Masks, a trap planted earlier by Gloria. Mayhem ordered Vanessa to overload the Masks, providing a distraction. However, their escape was cut short by the arrival Julio and Brad. Bruno and Sly arrived and the two teams prepared to face off.Though Matt offered Mayhem the choice to surrender, Mayhem refused, summoning the Switchblade via remote and giving V.E.N.O.M. the opportunity to escape. M.A.S.K. pursued, leading to a high-speed chase in the streets of Toronto. The battle once again came down to Matt and Mayhem. Though Mayhem was able to destroy the Thunderhawk, Trakker was able to use his Spectrum Mask to take down the Switchblade, forcing Miles to eject. While M.A.S.K. was able to capture the rest of V.E.N.O.M. (whom they turned over to G.I. Joe's custody), Mayhem escaped.
At some point, Mayhem hired out V.E.N.O.M. to Destro, who wanted them to retrieve the crashed body parts of the Transformer Astrotrain. Mayhem met up with Destro in Alice Springs, Australia to exchange Astrotrain's head, but the meeting was interrupted by Matt Trakker and Scarlett. While the G.I. Joe leader engaged Cliff Dagger, Mayhem retreated to the Switchblade. He tried attacking Joe sniper Sci-Fi, only to be stopped by Trakker in the Thunderhawk, and the two began dogfighting. During the battle, Trakker lured Mayhem into a trap, with Scarlett using Dagger and his Torch Mask to light the Switchblade on fire and forcing it down. Mayhem was able to escape as Matt retrieved the head.
Mayhem was one of many Earth villains contacted by Baron Karza, who offered to let them become his barons in exchange for accepting his dominion over Earth. Having dealt with him before, Mayhem defiantly proclaimed that Karza would be expelled from Earth once more.
Sometime later, Mayhem freed Vanessa and Bruno from prison, providing them their vehicles as well as new, upgraded Masks. The three then traveled to Spokane, Washington to retrieve Sly. Reunited, V.E.N.O.M. headed off to Mount St. Helens to intercept M.A.S.K., who were already preoccupied facing the Dire Wraith Shawn Berger. Before the heroes could finish him off, V.E.N.O.M. arrived and attacked. Knowing they couldn't face both Berger and V.E.N.O.M., Matt surrendered to Mayhem and proposed they work together to stop Berger, which Mayhem smugly agreed to. While V.E.N.O.M. fought off Berger's army, Matt and Gloria initiated a plan to stop the Wraith, absorbing the Ore-13 radiation from V.E.N.O.M.'s masks and vehicles and releasing it at the Wraith forces.
Now powerless, Trakker turned on Mayhem, attacking and beating him bloody with his fists. Matt took his gun, ready to finish him once and for all, only to be stopped by Gloria, who feared Matt becoming too much like his enemy. With that distraction, the other members and V.E.N.O.M. regrouped and were able to escape with Mayhem, stealing an ambulance to make their getaway.
As part of the Iron Ring, Mayhem participated in Joe Colton's attack on Cybertron, which awarded him the opportunity to take his new Outlaw vehicle into the field. Mayhem used the Outlaw to transport the Talisman, Garrison Kreiger, and Colton to a rendezvous with the rest of the alliance: Destro, Storm Shadow, and Shazraella, now possessing the body of a Cybertronian. The villains followed Shazraella into the depths of Metroplex to reach the core of the planet, where they planned to use the Talisman to wipe out the Cybertronians. Mayhem's arrogance and casual sexism did little to endear him to Shazraella and Storm Shadow, who threatened his life more than once. Colton merely shrugged off Mayhem's irritation, telling him to shut up and stop annoying everyone.
As the group descended ever deeper into the Titan, Colton cost them a whole hour due to setting up traps to stall his pursuers. The delay allowed Metroplex to locate them who transformed his internals to crush the aliens. The change in elevation sent Mayhem falling only for Shazraella to selflessly rescue him. As the group reached the end of the Titan's city mode, they were confronted by Sunstreaker whom Colton shot into stasis. As the Iron Ring made their way through Cybertron's underground, Mayhem laid down an elaborate hologram of an acidic river that was lethal even to Cybertronians. 500 meters from Cybertron's core, the planet began attacking the Iron Ring with bolts of energy prompting Mayhem to snap at Shazraella. Upon reaching the final stretch, Cybertron unleashed the Insecticon swarm to defend itself which Mayhem and Destro ineptly engaged. After Shazraella half-heartedly warned Mayhem of an Insecticon about to eat him, Colton tackled him down (saving him from the aforementioned Insection) and told his immature team to get in gear lest he start killing them all. When the group reached the core, they found Optimus Prime and Scarlett had beaten them there. Mayhem fought Lady Jaye and Roadblock before the Council of Worlds arrived to arrest everyone. In short order, Kreiger activated the Talisman, used Cybetron's energon to create New Prysmos and revealed himself to be an alien being known as "Merklynn" who teleported everyone else back to Iacon. While the fight had been taken out of Colton, Mayhem insisted they keep fighting...a stance he promptly abandoned when faced with Elita One's primed blaster in his face. Mayhem was then placed in a Cybertronian prison.
At some point, Mayhem was freed and was one of many figures present at a gathering of Earth's heroes and villains inside Trypticon, all united against the coming threat of Unicron. Mayhem engaged the Maximals in Venice with Sly Rax (and presumably the rest of V.E.N.O.M.), bickering with fellow supervillain Doctor X all the while.
- Obviously Miles Mayhem was never an Adventure Team member in the M.A.S.K. toyline (nor in the Joe line). He was added to the crew by IDW in order to tie the M.A.S.K. comic to G.I. Joe and made into the toyline's Sea Adventurer figure.
- Prior to this, the only times Miles Mayhem was associated with the G.I. Joe franchise was in the 2008 toy bio card for "Specialist Trakker", which stated that Mayhem's organization V.E.N.O.M. was a sub-division of Cobra (which seems obvious in retrospect), and a cameo appearance in a Big Lob-focused comic from the November 2010 issue of the G.I. Joe Collectors' Club magazine. 
- A younger Mayhem is depicted with the red hair of the Sea Adventurer figure in "Secret Raiders" and Revolutionaries, but is seen with the character's traditional white hair during a flashback in M.A.S.K.: Revolution.