With the Internet buzzing over the new trailer for Marvel Studios' "Avengers: Age of Ultron," one question going through the minds of many curious viewers is pretty basic: Just who is Ultron? Like many Marvel characters, the evil android's history is a long and complicated one -- but we'll unravel 45-plus years of comic book history right here.

Marvel Officially Releases First "Avengers: Age of Ultron" Trailer, Poster

A hallmark of fiction is the dramatic cliffhanger reveal, where a villain pulls off a mask and shows the hero who they're really facing. In 1968's "Avengers" #53 (by Roy Thomas, John Buscema and George Tuska), a new Masters of Evil -- an aptly named crew of villains teaming up to tackle the Avengers -- was formed, and managed to actually capture Earth's Mightiest Heroes. The team consisted of a number of familiar bad guys (The Melter, Klaw, Radioactive Man and Whirlwind), but they were led by a mysterious new villain known as the Crimson Cowl. At the end of the issue, the Cowl is dramatically revealed to be none other than the Avengers' own butler, Edwin Jarvis! But in actuality, that cliffhanger was a fake -- Jarvis was actually being hypnotized by the real brains behind the Crimson Cowl, the seemingly simple robot who shares the page with Jarvis. Yes, in Ultron's dramatic first appearance, he was not only not named, he was not even spotlighted.

Next issue, we learn Ultron's name, right after it is revealed that he is the actual brains behind the Crimson Cowl. It is surprising to note that when Ultron first appeared, he was already referring to himself as Ultron-5 (years before "Short Circuit's" Johnny Five). Not only did they quickly establish a trend of Ultron re-numbering himself every time he upgraded, but they chose to start the process with him already on his fifth incarnation. The Avengers defeated the Masters of Evil, but Ultron-5 escapes, leaving the heroes in the dark about who wanted them dead so badly.

The Avengers didn't have to wait long to find out. Just two issues later, they are attacked by a mysterious synthezoid known as the Vision (in an issue written by Thomas and drawn by Buscema and George Klein). Crafted by Ultron-5, Vision turns on his creator and help saves the Avengers. During their battle, the Vision takes advantage of Ultron-5's only weakness: two electrodes on his head (pretty notable weakness, don't you think?). Vision tricks Ultron into ramming into a wall, destroying the electrodes and causing Ultron's body to explode. The issue ends with a young boy discovering Ultron's head, in a scene accompanied by the Percy Bysshe Shelley poem "Ozymandias."

It is not until the next issue, however, that we finally discover Ultron's origins. The Vision wants to join the Avengers, and naturally, they want to know as much about him and Ultron as they can find out. They soon discover that Hank "Ant-Man/Goliath" Pym actually knows more than he realizes. His memory is refreshed and he recalls that he actually built Ultron. (Yes, Hank is a smart enough biologist and chemist to come up with a way to shrink a human being, make another shrunken human being grow wings and build a sentient robot!) After Ultron gained his artificial life, he turned on his creator and used the same brainwashing abilities he used on Jarvis to force Pym to forget his role in the villain's creation. With their worries about the Vision assuaged, the Avengers allow him to join the team -- and upon telling him the news, they famously learn that even androids can cry.

Ultron would be reborn in Avengers #66 (by Roy Thomas and Barry Windsor-Smith) at the hands of his own creation, the Vision. Ultron left hidden programming in the Vision, forcing him to help rebuild his master. The problem was, that that same issue saw the debut of the unbreakable metal known as adamantium, so when the Vision rebuilt Ultron, he used it -- making Ultron-6 the most powerful Ultron to date. Two issues later (with Sal Buscema and Sam Grainger stepping in for Smith), Ultron-6 upgraded himself and began to call himself the Ultimate Ultron. What made Ultron especially powerful was that the only thing that could destroy the adamantium was a device known as the molecular arranger, a device built into Ultron. Basically, the only thing that could destroy Ultron was himself. Luckily, Hank Pym disguised himself as the inventor of adamantium and when Ultron used a robot/human mind meld to learn of how to create more adamantium (to build an army of adamantium robots), he instead heard a simple message Pym repeated over and over in his head: Thou shall not kill. Ultron couldn't process that message, as the phrase was the opposite of everything he believed in. The resulting clash in his robot brain drove him insane, leading to blowing himself up.

Ultron was gone for a full five years -- an eternity in comic book bad guy time -- before returning for a two-part crossover between Avengers and the Fantastic Four, just in time for the wedding of former Avenger Quicksilver with former FF member Crystal. "Avengers" #127 (by Steve Englehart, Sal Buscema and Joe Staton) featured the Inhumans, the Avengers and the Fantastic Four all attacked by the giant android enemy of the Inhumans known as Omega. But at the end of the issue, we discover that Omega has been taken over by Ultron-7. In "Fantastic Four" #150 (by Gerry Conway, Rich Buckler and Joe Sinnott), we learn that Ultron was alive due to Maximus (the mad brother of the Inhuman's king, Black Bolt) salvaging Ultron's brain box after he exploded, and implanting it in Omega's android body. Ultron quickly betrayed Maximus and began to use his now amplified mental powers to kill everyone around Reed and Sue Richards' son, Franklin, who saved everyone by seemingly using up all of his mysterious powers to destroy Ultron.

Ultron-8 debuted in "Avengers" #161 (by Jim Shooter, George Perez and Pablo Marcos), where he actually teamed with Hank Pym, who suffered a mental breakdown and believed that Ultron is his ally and the Avengers his foes. Ultron kidnaps the Wasp, planning to transfer her mind into the body of a robot designed to be his queen. The process is halted by the Avengers, as Iron Man threatens to destroy Ultron's new "bride" unless Ultron gives up. Forced to retreat, Ultron leaves Iron Man to wonder if he would have actually gone through with his threat if Ultron had not backed own. Less than a year later, in #170-171, Ultron's "bride" -- Jocasta -- comes to life and seeks out Ultron, only to follow in the Vision's footsteps and turn on Ultron as well. The Avengers arrive, intent on destroying her, and end up helping her as the Scarlet Witch destroys Ultron with her probability altering powers, forcing his built-in molecular arranger (which allows him to build his body out of adamantium) to malfunction.

Very cognizant about what led to his previous defeat, in "Avengers" #201-202 (by David Michelinie, George Perez and Dan Green/Mike Esposito), Ultron hypnotizes Tony Stark and forces him to incapacitate the Scarlet Witch and deliver her to Ultron so he can kill her. He is terrified of her powers, believing she is the only person who could stop his plan to brainwash the human race and be part of Ultron's new hypnotized army. The Avengers ultimately defeat him by dropping him into a vat of molten adamantium. In what must have been a particular embarrassment for Ultron, it was the weakest Avenger, Hawkeye, who delivered the final blow that knocked him into the vat.

In "Marvel Two-in-One" #91-92 (by Tom DeFalco, Ron Wilson and a bunch of different inkers), Ultron used his connection to Jocasta to force her to save him from his frozen state by helping him transfer his consciousness into Ultron-10. The Thing ("Marvel Two-in-One" was a Thing team-up book) and Machine Man arrive, but Ultron uses his hypnosis trick to brainwash the Thing into attacking Machine Man. Machine Man and Jocasta (now free of Ultron's control) escape and return to take down Ultron and his plan to build an army of Ultrons. Jocasta sacrifices herself to stop Ultron, but her death only momentarily slows him down. It comes down to Machine Man extending his arm all the way down Ultron's throat until he finds and destroys parts inside of Ultron that aren't adamantium. (Big design flaw right there.)

The all-powerful entity known as the Beyonder decided he needed an Ultron for his Secret Wars, so he created Ultron-11 for just that purpose -- in "Marvel Super-Heroes Secret Wars" #1 by Jim Shooter, Mike Zeck and John Beatty. In the final battle between the heroes and the villains, the Human Torch takes Ultron out by going nova and burning out some non-adamantium part inside of Ultron. His head survived, however, and when the Thing returned to Earth, he brought the head of Ultron with him. Big mistake. Later, the Fantastic Four's home was attacked, and Ultron's head was lost in the rubble.

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Ultron-12 made his debut in the first issue of the "West Coast Avengers" ongoing series (by Steve Englehart, Al Milgrom and Joe Sinnott), working with the Grim Reaper in an elaborate plan to get revenge on Wonder Man and the Vision. Wonder Man's brain waves were used by Ultron-5 to create the Vision in the first place, the same process Ultron attempted to utilize with the Wasp and Jocasta, so Grim Reaper has some odd grudge against both the Vision and his resurrected brother. At some point, Ultron-12 develops human feelings for his "brothers" Wonder Man and Vision, and his "father" Hank Pym. He turns on the Grim Reaper and begins a sort of familial relationship with Pym, going so far as to call himself Ultron Mark 12, as it sounds more human. Unfortunately, Ultron-11 has been revived, taking control of a rescue worker who found his head in the rubble for the FF's building. After being united with a spare body, 11 and 12 clash as the latter attempts to prevent the former from killing Pym. In the end, Mark 12 "dies," but not before Wonder Man is able to singlehandedly defeat Ultron-11 by "shaking his brains out of his skull" -- which Wonder Man notes that he can't actually crush, since it was made out of adamantium. No, it really didn't make any sense.

The next Ultron is not really viewed as an "official" incarnation. Doctor Doom merged the consciousnesses of a bunch of different Ultrons into one body in "Daredevil" #275 (by Ann Nocenti, John Romtia Jr. and Al Williamson). Calling itself Ultron-13, it had multiple personalities and never appeared to be fully functional. After all, Daredevil literally defeated it by beating its head form its body with a stick.

A more realistic case for the official Ultron-13 came in "Avengers West Coast" #65-68 (by Roy & Dann Thomas, Paul Ryan and Danny Bulanadi) which found Ultron planning to treat humanity with a special process that would slowly turn everyone into robots under his control. The process worked on a few members of the Avengers (Tigra, Hawkeye and Quicksilver), but their teammates were able to reverse the transformation. Ultron initially teamed up with the Grim Reaper again, but once more, they ended as enemies -- only this time, it was the Reaper who seemed to turn good. Ultron attempted to take control of Hawkeye, but the Reaper also used his powers to drain a person's life force on the Avenger. The two cancelled each other out, allowing Wonder Man to smash them into each other.

Ultron was captured after appearing in several Spider-Man Annuals while searching for synthetic vibranium, and used his time in stasis to develop nano-bytes that could attack flesh and use them to reconstitute his body, becoming a new kind of Ultron (he called himself the Ultimate Ultron again, but let's go with Ultron-14) in "Avengers West Coast" #89 (by Roy and Dann Thomas, Dave Ross and Tim Dzon), Ultron added a new robot to his family when he used Mockingbird's brainwaves to create Alkhema. Ultron's plan was to wipe out the human race leaving only he, Alkhema and other robots they would build. When attempting to steal and detonate a nuclear missile, the Vision is able to disable the nuke before it explodes.

Ultron Stands Tall In New "Avengers" Art"

There was an Ultron-15 for a brief period of time, but he acted like Vision's drunk dad. The Vision and this Ultron agree to spend time together as father and son, but by the time the next Ultron showed up, this interaction was essentially glossed over and forgotten.

Ultron-16 debuted, seemingly having wiped out a whole country in the Heroes Return era "Avengers" #19 (by Kurt Busiek, George Perez and Al Vey). When the Avengers arrive, they're shocked to learn that there are hundreds more Ultrons ready to fight -- Ultron's dream of an army of Ultrons was finally coming true. Once again, his plan was to wipe out humanity, and this time, he kidnapped Hank Pym, Wasp, Scarlet Witch, Wonder Man, Grim Reaper and the Vision in an attempt to use their brainwaves to re-populate the Earth with new robotic beings. It was during this story that it is established that Ultron's brainwaves were based on Hank Pym's. The Avengers fought their way to the unnumbered "prime" Ultron in an iconic sequence where Thor lets Ultron know that they "would have words with thee." (I bet some form of that ends up in the movie!) Ultimately, the synthetic vibranium Ultron had been looking to steal in the Spider-Man Annuals come into play, taking the form of antarctic vibranium, which can destabilize any metal, including vibranium and adamantium. Eventually, Hank Pym uses the synthetic metal to destroy Ultron.

Ultron-18 appeared in the one-shot "Avengers: The Ultron Imperative" (by Kurt Busiek, Roger Stern, Steve Englehart and a host of artists), where Alkhema (who survived her last two team-ups with Ultron) found herself recreating Ultron again, his programming overriding her free will. This Ultron was not made out of adamantium, however, and once Alkhema allowed herself to be destroyed by Hawkeye, Ultron was able to be destroyed fairly easily. Ultron-18 resurfaced in "Iron Man" #47 (by Frank Tieri, Keron Grant and a bunch of inkers), though, as the head of the Sons of Yinsen, a cult that worshiped technology. Iron Man's armor had gained sentience in an earlier storyline, and we learned that it was Ultron-18 who manipulated those events. Ultimately, Iron Man works with Jocasta to defeat Ultron.

The next Ultron was the bad guy in the debut of Brian Michael Bendis and Frank Cho's "Mighty Avengers." Ultron had learned how to take over Iron Man's armor, but now due to a new technology known as Extremis, Iron Man's armor was literally part of him. as a result, Ultron ended up transforming Iron Man into a new Ultron. Eventually, Hank Pym was able to defeat Ultron by feeding it a computer virus that forced it to relinquish control back to Iron Man. This Ultron was the first Ultron to do away with the numbering system entirely.

Ultron next showed up in an unlikely place -- in the far reaches of outer space. In the crossover event "Annihilation Conquest" (by Dan Abnett and Andy Lanning, with art by Tom Raney and Scott Hanna), Ultron teams up with the technorganic race known as the Phalanx to conquer the Kree Empire, and threaten to conquer the universe. Luckily, the newly formed Guardians of the Galaxy were able to thwart his plans. Hmm... Ultron. Thanos. Avengers. The Guardians. There's some movie potential here!

Ultron continued his trend of appearing in odd places when he popped up in an "Avengers/Invaders" crossover by Alex Ross, Jim Krueger and Steve Sadowski. In the story, Ultron took over S.H.I.E.L.D.'s Life Model Decoys for a time before the android Human Torch is able to stop him.

Ultron then had a reunion with Hank Pym and Jocasta in "Mighty Avengers" #36, by Dan Slott, Khoi Pham and a few inkers. In it, Ultron starts calling himself Ultron Pym. Jocasta ends the battle by agreeing to go with Ultron, in order to help keep an eye on him.

And now we come to Ultron's biggest victory. When an Ultron head showed up in the pages of "Moon Knight," by Brian Michael Bendis and Alex Maleev,, the villain group known as the Intelligencia gain control of it and attempt to to merge it with the armor of a Galadorian Spaceknight. They seemingly don't succeed, but in "Avengers" #12.1, by Bendis, Bryan Hitch and Paul Neary, the merger occurs. The newly awakened Ultron takes off, and while Iron Man notes that this is bad news for the human race, he's unaware just how right he is.

Ultron soon returns with an army of Ultrons from the future, and proceeds to pretty much take over the entire planet. With only a handful of superheroes left to resist his rule, the "Age of Ultron" is underway (by Brian Michael Bendis and a few different artists, primarily Bryan Hitch, Brandon Peterson and Carlos Pacheco). A small group of heroes use Doctor Doom's time machine to go to the future where they attack Ultron at his home base. They are pretty much slaughtered, leading Wolverine and the Invisible Woman to use the time machine to travel back in time to before Hank Pym invented Ultron, Wolverine having decided that the only way to prevent the "Age of Ultron" is to kill Pym before Pym invents Ultron.

With that mission accomplished, Wolverine and the Invisible Woman discover that without Hank Pym, the world is possibly even worse off than it was under Ulton's rule -- well, probably not, but it's pretty damn bad. Wolverine goes back in time again, and stops himself from killing Pym! The two Wolverines and the Invisible Woman debate the subject with Hank, and they come up with a solution -- Hank writes a piece of code into Ultron, and then hypnotizes himself to forget he did so. Now, Ultron activates in "Avengers" #12.1, history is rewritten. Hank's code kicks in, and although Ultron fights it, his "father" wins and Ultron is shut down, effectively nullifying the Age of Ultron -- the title of both this story and the upcoming Marvel Studios film, although one is not an adaptation of the other -- before it starts.

And that's the current comic book status for Ultron; at least until the "Rage of Ultron" graphic novel is released next spring. His is a complicated and twisting history to be sure, but for all the changes in powers, personalities and version number, Ultron is always bad news for the Avengers -- and could be great news for theatergoers when James Spader voices the nigh-indestructible villain next summer in "Avengers: Age of Ultron."