Chitauri

"This... is a little resistance?" "Your force lacks... finesse."

- The Other and Loki

The Chitauri were a sentient species of cybernetically enhanced beings operating under a hive mind intelligence. Subservient to Thanos, they were most notable for being the first major threat to Earth that required the formation of the Avengers when they attempted to commence a planetary invasion as part of an alliance between Thanos and Loki.

When Iron Man utilized the power of the Infinity Stones in 2023, Iron Man decimated the entire Chitauri legion, their allies as well as their master Thanos, at the cost of his own life. After these events the Chitauri are now extinct.

Massacre of the Zehoberei
The Chitauri were Thanos' infantry during his attack against Zen-Whoberi, where he massacred a half of the Zehoberei species, in order to prevent overpopulation from condemning the planet. However, he chose to Gamora, a little Zen-Whoberi girl, to be one of his adoptive daughters whereas he gave his adoptive son Ebony Maw the order to give the Chitauri the command of killing half of the population.

Chitauri Invasion
"He has an army called the Chitauri. They are not of Asgard or any world known."

- Thor

When the exiled Loki allied himself with the warlord Thanos, the Chitauri were granted to him as his personal army to conquer Earth and gain the Tesseract.

Once having gained the Tesseract from S.H.I.E.L.D., Loki was able to open a portal to Earth, with the Chitauri fleet standing by, thanks to the help of a brainwashed Erik Selvig. The Chitauri immediately started to wreak havoc on New York City, destroying buildings and gunning down civilians in the streets. The National Guard could not deploy enough troops quickly enough to counter the invasion. Luckily, the Avengers arrived, having fought Loki repeatedly in an attempt to hinder his efforts at summoning the Chitauri. Soon after their arrival, a major battle ensued between them and the Chitauri. Not expecting such a resistance, the Chitauri were initially overwhelmed, but soon their numbers increased so much that the superheroes found some difficulties in containing them. Captain America took command of the Avengers as well as the police forces, and thanks to his command, the Avengers' powers were properly used while they fought the menace. Eventually, the World Security Council attempted to destroy Manhattan with a nuclear bomb in order to contain the Chitauri invasion, but Iron Man intercepted the bomb and disposed of it into the portal, where it impacted and obliterated the Chitauri Command Center, instantaneously disabling all Chitauri forces on Earth, thus ending the invasion.

After their defeat, pieces of Chitauri technology were recovered by S.H.I.E.L.D., HYDRA, Hammer Industries engineers , and Adrian Toomes' Crew.

Collector's Museum
A Chitauri was one of the specimens being held in Taneleer Tivan's museum before its explosion.

Infinity War
Many years later, Thanos ordered Chitauri to guard Nebula and also tasked him to reassemble her cybernetics. It was killed when Nebula tricked it by faking a malfunction and taking it by surprise.

Endgame
Following the end of the Infinity War, where half life in the universe was killed when Thanos snapped his fingers, the Avengers resulted in time traveling to the past in order to recover the Infinity Stones before these were destroyed so they could brought back to life all those who died. However, when the Thanos of 2014 was informed about this due Nebula's glitching, he captured the future self of his adoptive daughter and along the Black Order, the Outriders, the Leviathans, the Sakaarans and the Chitauri, traveled to 2023 with a new plan: destroy the universe and rebuild it as he wanted.

However, when it seemed that Thanos was going to win again, all of Thanos' victims came back to life and the decisive battle for the fate of the universe took place. As their fellow alien soldiers, many Chitauri warriors ended up losing their lives against the Avengers' forces. However, the battle came to an end when Thanos attempted once more to use the Infinity Gauntlet to erase half life in the universe only for Iron Man to snap his fingers with the Infinity Stones, causing Thanos' army, including the surviving Chitauri, to fade away and become extinct into nothingness before Thanos himself turned to dust.

Characteristic Traits
The Chitauri are a powerful, reptilian warrior race, a hybrid between organic beings and machines. They have a caste-like society, with each caste (nearly a different species in itself) fulfilling a different role in Chitauri society. They are controlled by a Mother Ship which never shows on the battlefield and act as one during the war. They have superhuman physical attributes, superior strategy, energy-based rifles and flying vehicles, but their main strength is in their great numbers. The Chitauri, as well as their sister species, have no sense of self-preservation, as they will attack their opponents regardless of how strong they may be.

Biology
The Chitauri are a cold-blooded, technologically advanced race. They are born as fully organic beings, but their soldiers are cybernetically enhanced at an early age with electronic neural networks and armor fused into their bodies. Infantry are now dependent upon chemical stimulants to enhance their strength and agility and internal reactors to power their cybernetic implants.

Despite the Chitauri's cybernetic augmentations, they are not seen to have any superhuman abilities such as enhanced strength, speed, or reflexes. They are seen to be agile and strong enough to climb on buildings and Leviathans with relative ease, but they were not quick nor strong enough to avoid or stand against Asgardians nor skilled Humans. They presumably have superior communication with each other via their Hive Mind, and thus are apt at strategy and coordination. Despite their interconnectedness, they are seen to be able to act independently, intelligent enough to engage in combat, assess various situations, and assist each other. A form of ailment that plagues their race was inadvertently discovered by firefighters and apprehended by Coulson's Team via a Chitauri Helmet salvaged from the Battle of New York. Due to their half biological and half cybernetic bodies, this "virus" has both biological and cybernetic properties. It interacts with biological tissue, such as affecting nervous tissue and lying dormant in epithelial tissue, but it is transmitted by electrical shocks, such as the static of rubbing against an infected item. In humans, it causes a gradual buildup of electrostatic energy in the brain, eventually releasing a burst of 2,000 megajoules. This massive amount of energy leaves a burn mark on the forehead and just before erupting causes nearby metallic objects to float, caught in the resulting electric field. Additionally, the virus alters the host's molecular density and polarity, resulting in the affected bodies found dead floating in the air.

Allies

 * Thanos † - Master
 * The Other † - Commander
 * Outriders † - Sister Species
 * Sakaarans †
 * Leviathans †
 * Black Order
 * Corvus Glaive †
 * Cull Obsidian †
 * Ebony Maw †
 * Proxima Midnight †
 * Loki † - Former Commander

Enemies

 * Zehoberei - Victims
 * Gamora's Mother †
 * Guardians of the Galaxy
 * Gamora
 * Nebula
 * Avengers
 * Steve Rogers/Captain America
 * Tony Stark/Iron Man †
 * Thor
 * Bruce Banner/Hulk
 * Natasha Romanoff/Black Widow †
 * Clint Barton/Hawkeye
 * Peter Parker/Spider-Man
 * Sam Wilson/Falcon
 * James Rhodes/War Machine
 * Wanda Maximoff/Scarlet Witch
 * Carol Danvers/Captain Marvel
 * Scott Lang/Ant-Man
 * Erik Selvig
 * S.H.I.E.L.D.
 * Masters of the Mystic Arts
 * Ancient One †
 * Stephen Strange/Doctor Strange
 * Wong
 * United States Army
 * New York City Police Department
 * Beth
 * Guardians of the Galaxy
 * Peter Quill/Star-Lord
 * Drax the Destroyer
 * Mantis
 * Groot
 * Rocket Raccoon
 * Golden Tribe
 * T'Challa/Black Panther
 * Shuri
 * Bucky Barnes/Winter Soldier
 * Dora Milaje
 * Okoye
 * Jabari Tribe
 * M'Baku
 * Border Tribe
 * Wakandan Royal Guard
 * Brunnhilde/Valkyrie
 * Hope van Dyne/Wasp
 * Sakaaran Rebellion
 * Korg
 * Miek
 * Ravagers

Trivia

 * In the Ultimate universe, the Chitauri are shapeshifting race kin to the Skrulls, but far more mutated and dangerous. They were one of the first threats faced by the Ultimates, but their background story reveals that they were present on Earth since World War II.
 * Following their appearances in The Avengers, the Chitauri were introduced for the first time in the Mainstream Comic Universe. This version resembles much more of their Cinematic counterparts.
 * The Marvel Cinematic Universe version of the Chitauri is similar to the Phalanx, a cybernetic alien race from the comics who communicated through a hive-minded intelligence.
 * The name "Chitauri" derives from, the name of a binary star in the constellation.

Behind the Scenes

 * Joss Whedon revealed that he chose to include the Chitauri over Skrulls or Kree because this particular race didn't have any wide background story and they could be used even for a small part.