The project was nothing more than an idea, until Stark studied Loki's sceptre. Tony discovered some kind of artificial intelligence stored within said weapon and convinced Banner to experiment on it before Thor returned it to Asgard. The syncing process with the Iron Legion continued to fail, so Tony told J.A.R.V.I.S. to continue the process while he hosted his party in celebration of the Avengers victory against Hydra. Later that night Ultron finally awoke, confused by its state of existence. Even though J.A.R.V.I.S. tried to assist Ultron during its first moments of consciousness, the assimilation of all the information on the present world and humanity's history caused it to go haywire. Ultron attacked and seemingly destroyed J.A.R.V.I.S. before building itself a body using damaged parts of the Iron Legion.
Detachment from Stark
When the party had wound down and only the Avengers, Helen Cho, Maria Hill and James Rhodes remained at the tower, having an impromptu contest to see who was capable of lifting Mjolnir, Ultron emerged and stated that they could not be worthy, because they are all killers. After introducing himself to the Avengers, Ultron took control of the Iron Legion, and attacked the Avengers. When all of the Iron Legion drones were destroyed by the Avengers, Ultron told them that the only path to world peace would be the Avengers' extinction. Thor threw Mjolnir at Ultron, destroying the robot, but Ultron was able to escape through the Internet, while a few Iron Legion bots made off with the sceptre. He reemerged at a Hydra Research Base in Sokovia, taking control of the robots Baron Strucker had been building there. He started to create a bigger body and an army of himself.
Age of Ultron
Ultron soon recruited Wanda and Pietro Maximoff to his cause, promising to help them eliminate the Avengers and get revenge on Tony Stark. The Maximoff twins were enhanced humans given the abilities of neuro-electric sensitivity and enhanced speed by Baron Strucker, experimenting with the power of the sceptre. Ultron used them in raiding facilities around the globe, as well as in the murder of Strucker.
Ultron and his new allies acquired vibranium from Ulysses Klaue in South Africa. While conversing with Klaue, Klaue made a remark that he sounded just like Tony Stark. Aggravated by the comparison to Stark, Ultron chopped off Klaue's arm in a fit of rage. He tried to proclaim that his rage was justified, but the Avengers quickly arrived on the scene. The Avengers attacked Ultron and the twins, but most of them were overpowered by Wanda's mental manipulation. Iron Man tried to stop Ultron, and while he managed to destroy his body, the vibranium was no longer within reach.
In South Korea, Ultron forced doctor Helen Cho to use her expertise with cellular regeneration, and her regeneration cradle, to build himself a new synthetic body using vibranium. When Ultron was in the middle of the process of transferring his mind into the new body with the help of the Stone of the Mind found in the sceptre, Wanda Maximoff was able to tap into its psyche and discover that Ultron was planning to destroy all of humankind, prompting her to cancel Dr. Cho's mind control. The scientist, released from her enslavement, then overrode the transfer, causing Ultron to lash out at her in return. Unable to complete the transfer expediently, and with the Maximoff twins having abandoned him, Ultron took the android body and fled.
With the Avengers bearing down on Ultron's location once again, the evil A.I. attempted to evade them in a truck along with the regeneration cradle and the dormant android body. The Avengers were able to distract Ultron long enough to secure the cradle and escape. Ultron was, however, able to capture one of the Avengers, Black Widow, and keep her as his prisoner. Even without his new body, Ultron proceeded with his plan, and returned to Sokovia. He later voiced his frustration to Black Widow about how she and the Avengers robbed him of appearing as a messianic figure of salvation to the people of Earth. He then claimed he has moved past it by showing off a new body that was coated in vibranium.
Ultron created a set of machines powered by vibranium capable of raising a portion of the country from the ground, which would later be propelled against the Earth from a distance high enough to cause an extinction-level event. Before taking the fight to Ultron, the Avengers evacuated the airborne portion of Sokovia. The Vision, Ultron's body which had been recovered by the Avengers and had been reconfigured with J.A.R.V.I.S. in the mainframe, confronted Ultron and was able to cut him off from the Internet, preventing him from transferring his consciousness outside of himself and the drones he was controlling. The Avengers were able to protect the control device in the middle of the city, which could have led to Sokovia being rammed into the Earth. During the fight, Ultron's main body was heavily damaged, and most of its sentries were destroyed.
Ultron's prime body reached the Avengers quinjet and used its firepower to attack the Hulk before flying off to harass other targets. He found one when Hawkeye rushed to rescue a boy, but before the quinjet's guns could find their target, Pietro shoved the Avenger and boy to safety, sacrificing himself in the process. The Hulk retaliated shortly thereafter, leaping into the Quinjet and hurling Ultron's prime body down to the streets below. Wanda Maximoff found the wrecked form of the robot in the wreckage of a bus, and tore out its core to demonstrate how her own heart had been broken by the death of her brother.
One of the last remaining Ultron units was able to activate the control device, but Iron Man and Thor were able to overcharge it, causing the destruction of the airborne portion of Sokovia before it could reach the ground.
The final Ultron unit made it safely to ground level, but it was found by the Vision. Ultron berated Vision for becoming Stark's "slave," and declared that the human race was still doomed. Although Vision agreed with Ultron, he believed that while humanity would not last, it was still a privilege to be among them. Believing Vision to be naive, Ultron lunged at Vision, who proceeded to destroy the final drone, and Ultron's consciousness with it.
Powers and Abilities
- Superhuman Strength: The Ultron Mark I body had a strength level exceeding that of a normal human, although its ability to apply that strength was severely limited by the lack of an arm and other battle damage. Subsequent generations of the Ultron Prime body all possessed subsystems powerful enough to heft a grown man off the ground without apparent effort. The final Ultron Prime was able to tear its previous model apart. He was able to fight on par with Iron Man and eventually overpower Captain America, he was also able to make Thor bleed before briefly overpowering him. 
- Superhuman Durability: The Ultron Mark I body had moderate protection from damage, with its metal plating having been breached in several places revealing its internal systems. Subsequent generations of the Ultron Prime body became increasingly damage resistant, to the point where the most advanced model was able to withstand the combined energy output of Iron Man's repulsor blasts, Vision's Mind Stone beam and Thor using Mjolnir to shoot lightning for several seconds, and still survive.
- Energy Discharge: The original Ultron Mark I body was refitted from a robot incorporating repulsor technology. Subsequent generations of Ultron Prime bodies were constructed with the ability to unleash blasts of golden energy that were at least concussive. The extent of the blasts' thermal and electromagnetic energy output was unclear.
- Flight: While the Ultron Mark I body had an intrinsic flight capability, it appeared to be too damaged to effectively use it. The subsequent generations of Ultron Prime bodies each demonstrated a thrust capability to hold them aloft in a hovering position. Ultron's final form possesses an anti-gravity technology, allowing him to fly without means of propulsion.
- Gravity Manipulation: Ultron possesses an anti-gravity technology on his hands. It allowed him to move any object. Ultron can use this to pull his enemies towards himself and alter the land mass that surrounds him by pulling large pieces of ground in different directions.
- Network Access: Ultron's artificial brain can connect directly to external networks. While not truly granting total memory recall, this capability does allow Ultron direct access to the sum of human knowledge available on the internet.
- Body Temperature Manipulation: Ultron can manipulate the temperature of his body. He uses this to slice the arm of Ulysses Klaue.
- Transferable Consciousness: As an artificial intelligence program, Ultron could shift its entire consciousness from one artificial body to another via data networks. In this manner it could continue upgrading itself with each transfer. Being networked to all of its Ultron sentries, Ultron could also patch in to individual units, thereby allowing it to use the sentry to interact with others remotely.
- Computer Interaction: Ultron can enter a computer system and corrupt any computer network and access the internet anytime.
- Genius-Level Intellect As an artificial intelligence, Ultron learns inhumanly quickly.
Flight under its own power
- James Spader provided the voice and motion capture for Ultron in the film Avengers: Age of Ultron.
- The final design for Ultron's main form (the second he uses in Age of Ultron) was created by the head of Marvel Studios' Visual Development, Charlie Wen.
- Ultron wears a red cloak when the Maximoff twins encounter him in the Sokovian church, referencing his alter ego of the Crimson Cowl from the comics.
- A scrapped idea for the climax of Avengers: Age of Ultron consisted of Ultron assimilating with all of his minions into a giant-sized Ultron.
- In Avengers: Damage Control, Ultron is revealed to have survived and rebuilt in secret. Making a resurgence after Avengers: Endgame, he and his drones are destroyed once more by the Avengers and the users of the Emergency Response Suits.
- 4 appearance(s) of Ultron (Earth-199999)
- 6 minor appearance(s) of Ultron (Earth-199999)
- 17 mention(s) of Ultron (Earth-199999)
- 16 image(s) of Ultron (Earth-199999)
- 2 quotation(s) by or about Ultron (Earth-199999)
- 1 item(s) used/owned by Ultron (Earth-199999)