The Chitauri made their first appearance in The Ultimates #8, published in November 2002. They were co-created by writer Mark Millar and artist Bryan Hitch as part of the Ultimate Marvel imprint. This imprint was designed to reimagine classic Marvel characters and concepts for a modern audience, free from decades of continuity. Millar and Hitch's goal with the Chitauri was to create a more visceral and terrifying version of Marvel's classic shapeshifting aliens, the Skrulls. They sought to move away from the “little green men” trope of the Silver Age and design an alien threat that felt more grounded, sinister, and ideologically dangerous. Their name is derived from Zulu mythology, where the term Chitauri refers to “the dictators” or “the ones who tell us the law,” fitting their imperialistic nature in the comics. Their introduction to a global audience came a decade later in the 2012 blockbuster film The Avengers, directed by Joss Whedon. For the Marvel Cinematic Universe, the Chitauri were fundamentally redesigned. This change was born of both creative and legal necessity. At the time, the film rights to the Skrulls were held by 20th Century Fox as part of the Fantastic Four package. To avoid any legal entanglements and to differentiate the MCU's first major alien invasion, Marvel Studios reimagined the Chitauri. They were stripped of their shapeshifting abilities and recast as a bio-mechanical drone army. This strategic decision allowed the MCU to have its massive alien invasion without using the Skrulls, saving that concept for a later, more nuanced introduction in Captain Marvel. The MCU's version, with its iconic Leviathans and skeletal warriors, has since become the definitive image of the Chitauri for millions of fans.
The origin and nature of the Chitauri differ drastically between their comic book roots and their cinematic adaptation. Conflating the two is a common error; they are, for all practical purposes, two distinct species sharing the same name.
In the Ultimate Marvel continuity, the Chitauri are an ancient and malevolent species of reptilian shapeshifters. They are not a mindless horde but a cunning, patient empire that has been at war with other cosmic powers, such as the Kree, for millennia. Their primary method of conquest is not overwhelming force but insidious infiltration. Their history with Earth-1610 is a long and dark one. The Chitauri observed the planet for centuries, but their direct interference began in the 20th century. During World War II, a Chitauri commander operating under the name Herr Kleiser allied himself with the Nazi party. The Chitauri provided the Nazis with advanced technology in the hopes of destabilizing the planet and preparing it for a full-scale takeover. Their goal was to use humanity's own self-destructive tendencies to weaken the globe before they revealed themselves. This covert operation brought them into direct conflict with the Allies' super-soldier, Captain America. The ideological and physical battle between Captain America and the shapeshifting Herr Kleiser became a cornerstone of their long-standing animosity. Decades later, the Chitauri infiltration was uncovered by S.H.I.E.L.D. and its new superhero team, The Ultimates. The aliens were revealed to have embedded agents in governments and military structures across the globe. Their ultimate plan was to activate a planet-destroying bomb hidden in the solar system if their takeover was resisted. They viewed other species not as beings to be conquered, but as livestock to be consumed. The Ultimates, led by Captain America and Iron Man, managed to repel the Chitauri fleet and defeat Herr Kleiser in a brutal final battle, seemingly ending their threat to Earth.
The MCU's Chitauri have a far more straightforward, and tragic, origin. They are a species of sentient, six-fingered reptilian humanoids who were subjugated and transformed by the Mad Titan, Thanos. Hailing from the polluted, hive-like Chitauri Prime, their entire race was cybernetically altered, turning them into a slave army connected by a collective consciousness—a hive-mind. Each Chitauri soldier is a fusion of organic flesh and machine, neurally linked to a central command ship, or “mothership.” This link grants them tactical coordination on a massive scale but is also their greatest weakness: if the mothership is destroyed, the command signal is severed, and every soldier and vehicle connected to it instantly deactivates, collapsing like a puppet with its strings cut. They are not infiltrators; they are the blunt instrument of Thanos's will, a disposable legion to be thrown at any world that resists him. Their story in the MCU begins in earnest when Thanos forges a pact with the disgraced Asgardian prince, Loki. In exchange for retrieving the Tesseract (containing the Space Stone), Thanos grants Loki command of a Chitauri army. This army is led by Thanos's vizier, a hooded figure known only as The Other. Following Loki's plan, the Chitauri invade Earth through a wormhole opened above New York City. The ensuing “Battle of New York” is a devastating event that forces the formation of the Avengers and serves as Earth's violent awakening to the cosmic horrors of the galaxy. The legacy of this single invasion defines much of the subsequent MCU. Salvaged Chitauri technology fuels a black market for alien weaponry, leading to the rise of villains like Adrian Toomes (Vulture). It also pushes figures like Tony Stark to develop more advanced armors and defense systems, like the Ultron Program, in a desperate attempt to protect the planet from a similar, or worse, future attack. A past version of the Chitauri army later returns alongside Thanos for the final Battle of Earth in Avengers: Endgame, where they are ultimately erased from existence by Iron Man's use of the Infinity Gauntlet.
The fundamental differences between the comic and film versions are most apparent in their biology, technological doctrine, and societal structure.
This storyline, spanning The Ultimates #7-13, is the definitive Chitauri arc in the comics. The plot unravels the shocking truth that a shapeshifting alien race has been manipulating humanity for over 60 years. The narrative's climax reveals that the Chitauri were the architects of the Nazi's advanced weapons program and that their commander, Herr Kleiser, has been a personal nemesis of Captain America since 1945. The Ultimates are forced to fight a war on two fronts: a public, city-destroying battle against the revealed Chitauri fleet, and a covert mission to stop a hidden Chitauri bomb from destroying the solar system. The storyline ends with the Hulk being deployed as a weapon of last resort to find and brutally kill Kleiser, ending the immediate threat to Earth. This event cemented the Chitauri as cunning, patient, and monstrously evil infiltrators.
Featured in the 2012 film The Avengers, this is the most famous event involving the Chitauri and one of the most pivotal moments in the entire MCU. After Loki opens a portal using the Tesseract, the Chitauri army pours into Midtown Manhattan. For the first time, Earth's mightiest heroes must assemble to face a threat no single one of them can handle. The battle is a showcase of the Chitauri's military might, with their endless stream of soldiers, agile Chariots, and building-sized Leviathans overwhelming conventional military forces. The event establishes the scale of cosmic threats, provides the motivation for the Avengers to become a permanent team, and leaves a lasting scar on the world, both physically and psychologically. The leftover Chitauri technology becomes a recurring plot device, demonstrating the long-term consequences of their brief, violent invasion.
The climactic final battle of Endgame features the return of the Chitauri as part of a 2014-era Thanos's full military force. Transported to the future ruins of the Avengers Compound, they join the Outriders, the Sakaarans, and the Black Order in a final, desperate war against a resurrected army of heroes. This time, they face not just the Avengers, but the armies of Wakanda, the sorcerers of Kamar-Taj, the Ravagers, and the remaining forces of Asgard. The battle demonstrates that the Chitauri were just one component of Thanos's vast and diverse warmachine. Their existence, along with the rest of Thanos's forces, is brought to a definitive end when Tony Stark sacrifices himself, using the power of the Infinity Stones to wipe them from reality.
Following the immense popularity of the MCU, a version of the Chitauri was eventually introduced into the main Marvel comics continuity (Earth-616). This version is distinct from both the Ultimate and MCU incarnations. They are a warrior species known as “the Great Swarm,” capable of breeding specialized soldiers tailored for specific planets and combat scenarios. Their most notable conflict was against the new Nova (Sam Alexander), after they came to Earth to reclaim a powerful Chitauri artifact, the War-Bringer helmet, which had bonded with a human. While formidable, they lack the cultural and narrative impact of their Ultimate and MCU counterparts.
The Chitauri have appeared in several alternate timelines within the Disney+ series. In the episode “What If… the World Lost Its Mightiest Heroes?”, Hank Pym's revenge plot kills off the Avengers candidates before they can assemble. Nick Fury and Loki are forced to team up to defend Earth, with the Chitauri invasion looming as their first major test. In another timeline shown in “What If… T'Challa Became a Star-Lord?”, T'Challa successfully convinces Thanos to abandon his genocidal plans. In this reality, Thanos never becomes a galactic tyrant, meaning the Chitauri were never amassed into his personal army and the Battle of New York never occurred.