Despite the many villains who have been reintroduced to new audiences in the MCU, one of the Avengers' coolest enemies, the Ultimate Marvel Universe's Liberators, may never get an opportunity to make the transition. This team of evil Avengers similar to DC's Crime Syndicate was created to mimic or surpass members of the famous American superhero team. Despite being extremely realistic and cinematic, their motivations and characters may be too politically driven, graphic or dependent on their secret puppet master, Thor's half-brother Loki, for Disney to give them a shot any time soon.
Created by writer Mark Millar and artist Bryan Hitch for the Ultimates 2 series from 2005, the Liberators are formed by a coalition of the world's other superpowers wanting to push back against the rise of power in the U.S. military complex, boosted by S.H.I.E.L.D. and their relationship with the Ultimates, their universe's version of the Avengers. The Ultimates' participation in the invasion of Iraq results in North Korea, Russia, Syria, and other countries investing time and resources into creating a team of multinational supervillains. Every member ranging from the Crimson Dynamo to the Insect Queen are volunteers who have had their bodies experimented upon and modified, granting them abilities that match, or surpass, those of the Ultimates. Accompanied by an impressive army of foot soldiers, the Liberators gain important intel from Hank Pym and Black Widow, whose betrayal helps the Liberators prepare for their big moment.
After months of manipulation that leaves the Ultimates broken and unprepared, the Liberators invade the United States, destroying the Triskelion and disabling much of the government as well as members of the Ultimates. Many of Ultimate Marvel's heroes are later imprisoned, some even prepared to be executed publicly to end their threat to the free world. Every member of the Liberators has their own reasons for participating, ranging from political to personal, and it looks like they have actually won. Unfortunately, their own arrogance and underestimating of the Ultimates' capabilities leads to their downfall, as these Avengers gradually gain a second wind, defeating and killing most of the Liberators in battle. In the end, it's revealed that events throughout the entire series including this are all thanks to the Liberators' god Loki, who has chosen to make Thor's Midgardian realm his personal playground of revenge and suffering.
Although the Ultimates are the blueprint for much of the MCU's Avengers, the Liberators' themes and attitude may not mesh well with the general direction of the Marvel Cinematic Universe. Writer Mark Millar reinvented and reinterpreted the Avengers for the modern age, showing a team not only battling supervillains but also ideological and political opponents. The Liberators are literally created to fight against them and their government, whose employ of superheroes has upset the balance of world powers. This team believes themselves to be the heroes fighting back against their great Satan. Ultimates 2 is full of gore, death, dismemberment, and other mature situations that have only been touched upon briefly in Marvel's films. The Liberators are also too reliant upon Loki, who joins in order to be a counterpoint for Thor in the Ultimates. Gleefully watching the events unfold, he shows little remorse or concern when the Liberators begin to lose, taking it upon himself to get his hands dirty and expose the extent of his manipulations here.
In the end, the Liberators are operating on a different level of storytelling that the MCU is not ready for or unprepared to go in that direction. While the MCU version of Loki shows considerable power and trickery, he has constantly allied with others to accomplish his own goals unlike the Ultimate version Loki, whose threat is only nullified when Thor returns to help the Ultimates. Although the Liberators won't be in the MCU anytime soon, their battle with their Avengers forever changes the heroes who realize that their symbolism won't always inspire the best in the world.