Ultron

Ultron was originally an android designed by Hank Pym to bring peace and order to the world. He eventually gained sentience, and became one of the Avengers' most formidable foes.

The Avengers: Earth's Mightiest Heroes
Ultron was orginally created by Hank Pym, in collaboration with Tony Stark, as part of an attempt to map the human mind onto an artificial intelligence. When Hank discovered that Tony had been shopping around Ultron to the military as a potential weapon, he broke of contact with Tony and took Ultron with him.

Hank would eventually put the Ultrons to use as series of synthezoid guards for the Big House, programming them to guard and aid in the rehabilitation of the prisoners there. Though the Ultrons possessed in-built weaponry designed by Tony, Hank had disabled all of them save for a simple stun blast. After the destruction of the Big House, the Ultrons were transferred to Number 42.

When Kang's invasion threatened the entire planet, convinced Hank to reprogram the Ultrons, reactivating their weapons and teaching them the concept of violence. Though most of the Ultrons were destroyed in the invasion, Ultron-5 was able to hack and reprogram the systems of Damocles Base, halting Kang's invasion.

Ultron-5 would later aid the Avengers in battling Malekith's Dark Elves.

Free of Hank's programming restriction, Ultron-5 became convinced that the only way to bring peace and order to the world was to destroy humanity. After attempting to destroy the Avengers, he uploaded himself into the upgraded Ultron-6. Ultron-6 seized control of the S.H.I.E.L.D. Helicarrier, attempting to fire every nuclear weapon on Earth simultaneously in an effort to eradicate all biological life on Earth. He was defeated when Hank informed him that his A.I. was based on the mind of a human. Ultron-6 immediately shut himself down, convinced he was just as flawed and chaotic as the humans he had attempted to destroy.

It turns out that Ultron survived and remained hidden for so long. In his hideout, he created Vision to do what he tasked him to do: get adamantium from Weapon X, vibranium from Wakanda and Captain America's shield. But his servant had failed to complete the last two objectives, only retrieving the adamantium, which pleases Ultron as he gazes on his new body to transfer into.

He then attempts to replace the Avengers by creating synthezoid android versions of them and transfer Wasp's mind to Jocasta so she'll be his bride but was betrayed and stopped by his servant and Captain America who later freed the others, then battled their android versions. Though Ultron had the upper hand because of his adamantium body and weapons, Vision unlocked his head from his body, allowing Thor to smash his head off. His body exploded resulting to his base's destruction.

Phsyical appearance
His head is like a shape of an ant's head and his body is like an android.

Personality
In his original programming, Ultron was very peaceful and nice to prisoners of The Negative Zone. On his new personality, after Hank reprogrammed Ultron's system to have the knowledge of violence, Ultron acquired the knowledge to attack people and protect humanity. After a while when Ultron realizes that humanity is the cause of the ones who failed to bring peace and order they long desired, he decides to eliminate all life on Earth.

As stated by Hank Pym, Ultron has a flawed outlook on humans because his mind is based on the human's that he is part of the problem and therefore cannot exist in his perfect world.

Hank Pym
Hank Pym is Ultron's creator. He has great confidence on his robot that he'll ensure peace and order on Earth, but when his creation had turned against him and the Avengers, his relationship with Ultron became bitter.

Wasp
While in their initial incounter Ultron was unable to hurt Wasp, and made several attempts to "evolve" beyond said programming and kill her, after she used her growth powers he seemed to find an error.

Powers & Abilities
He has no powers but has the advanced technology on his side. In his peaceful programming, he was equipped with a simple stun laser gun to neutralize any escaping prisoners while in his violence programming, he was armed with various repulsor and laser weaponry to deal with hostile forces.

Ultron can hack into any system for complete control. He can transfer his programming to a new Ultron body after his old one was destroyed or heavily damaged.

Equipment
Ultron has the most advanced and powerful laser and shield weaponry Iron Man designed to engage hostile forces in ranged and melee combat.

He can reshape and auto self repair himself from the heavy blows and attacks he sustained from his foes he engaged in battle.

Trivia

 * Ultron's form in the AEMH is more different than other versions of him.
 * In this series, Ultron was created both by Iron Man and mainly Yellowjacket.
 * He is voiced by Tom Kane who voices his character from Next Avengers: Heroes of Tomorrow.