With Avengers 2 Age of Ultron just around the corner, there are still so many questions to be answered about Marvels future and Phase 3. How does Ultron fit into the grand scheme of the MCU? Will Thanos be in Avengers 2? What will be happening in Avengers 3?
Recently revealed in new Avengers 2 promo art was this description of Ultron's origins...
First discovered as a simple computer program hidden among the ruins of the Chitauri invasion of New York, the being known as Ultron soon completed its development into a sophisticated artificial intelligence after some experimentation by Tony Stark. Ultron's first shocking ultimatum upon gaining consciousness was to declare the human race it's enemy. Setting out to exterminate all life on the planet, be unstable and emotional Ultron seeks to upgrade its mechanical body to an ultimate, unstoppable form. With an army of robotic drones and the ability to enter and corrupt any computer network, Ultron will stop at nothing to see humanity wiped out.
So basically Ultron will originally be some sort of dormant Chitauri computer artificial intelligence brought to Earth in Avengers (2012). Ultron will then be experimented on by Tony Stark AKA Iron Man, and become the villain we see him as now.
When Ultron wakes up in [The Avengers: Age Of Ultron](movie:293035), he'll suddenly have the desire to end all human life. But why? Does it have something to do with the Chitauri invading Earth and his programming tells him to just keep attacking? Or is he just totally bonkers? What kind of program was he originally anyway?
From the above description, it looks as if Ultron was some normal AI within some Chitauri technology that Tony Stark is tasked with analyzing. Stark likely goes too far with an experiment, and successfully separates Ultron from this technology, giving him sentience and freedom. Why then, if a human were to free Ultron, would he just turn around and want to end all life on Earth? The answer may lie in Phase 3...
Avengers 3 is the Infinity War Part 1 & 2. Now when you wage a war, what do you need? An army. Two or more opposing armies actually. So what armies will be at war in Avengers 3? I think Thanos and his legions of Chitauri are a good place to start. Thanos has been building his forces for a while now, and is gearing up for war. Recruiting Loki, Ronan, and likely other powerful creatures to possibly lead portions of his army for him when the time comes. Obviously Loki failed because of the Avengers, and Ronan betrayed Thanos and was killed by the Guardians.
So what forces do we know of that could possibly fight that type of an army? There's two that come to mind. The Nova Corps, and the Kree.
The Nova Corps are a strong force, but as we saw in Guardians of the Galaxy, their home world Xandar was nearly destroyed by just Ronan and his small contingent of troops. I doubt they have the numbers to really be the larger army against Thanos.
So then its the Kree right? It seems most likely that the Kree race of aliens would oppose Thanos' army. We've seen glimpses into the lives of the Kree here and there. In Agents of SHIELD...
and in Guardians of the Galaxy...
Remember this scene? In the beginning of [Guardians of the Galaxy](movie:424073), Nova Prime, played by Glenn Close, argues about the actions of Ronan the Accuser. The Kree leader basically says Ronan's actions are none of his business and to leave him and the Kree alone. He seems to be dodging the issue. What if this leader of the Kree knew about Ronan's connection to Thanos, and was avoiding getting involved because it would incite an all out war between the Kree and the Chitaturi? Surely if the Kree came to Xandar's aid against Thanos, they would be taking sides. It would be the spark that starts the fire.
Obviously the Kree are avoiding this inevitable war and trying to remain neutral against Thanos. What could possibly send the Kree over the edge and force them to gear up and fight the Chitauri? Could it be the death of their greatest hero?
Captain Mar-Vell of the Kree empire. He is a Kree captain, and has been often referred to as the Kree's greatest hero. He is the Kree's Captain America and Iron Man rolled into one. What if Avengers 3 Part 1 opens with a battle between Thanos and Mar-Vell, where Thanos slays Mar-Vell and it is shown all around the galaxy. The Kree might go to war with Thanos after he kills one of their greatest.
They could set up Mar-Vell in [Guardians of the Galaxy 2](movie:1081113), having him fight alongside the Guardians against whatever galactic wide threat was facing them. It'd make sense if the threat was great enough that the Guardians and Mar-Vell would cross paths. We'd grow to love Mar-Vell, and then Thanos kills him. It could be the first real action Thanos does, as so far all he has done is talking. It would be his first show of true power and really start the Infinity War.
Following the events of Mar-Vells death, his powers could be transferred to Carol Danvers. This leads us directly to....
Captain Carol Danvers joins the MCU and becomes an incredible new hero. Joining the war, she sides against Thanos and tries to continue on the legacy of Captain Mar-Vell. The Kree team up with the humans, and form an alliance. The alliance leads to unleashing the Terrigen Mists, which we have all seen already in [Agents of S.H.I.E.L.D.](series:722469). This will unlock the powers of people everywhere with the dormant Inhuman gene, and leads us directly to....
Following the arrival of the Inhumans, we have Infinity War Part 2. Considering the Kree's direct connection to Captain Marvel and the Inhumans, the potential for the Kree joining the fight against Thanos is enormous. The Kree's greatest war hero gave his powers to a human girl, and the new army of Inhumans could be used by the Kree to fight Thanos and his army of Chitauri.
So lets go back. Ultron is a dormant Chitauri AI, who is given some freedom by Tony Stark. He immediately determines that he must end all life on Earth upon waking up and becoming sentient. Why? Its very likely that Ultron, being a part of the Chitauri computer systems, is well aware of Thanos' plans to come to Earth.
Thanos knows the Kree will try to use the Inhumans against him, so he'll attempt to kill the Earthlings before the Kree can get that chance to transform them. Ultron knows that if Thanos comes to Earth, he would destroy Ultron and turn him back into a simple AI again, and not the free sentient being he is now. Ultron makes the decision to kill us FOR Thanos, this way Thanos has no need to come to Earth. Ultrons actions would spare Ultrons life and grant him his freedom.
His actions are also selfish and that of a coward. If Thanos should ever meet Ultron, it is quite likely that conversation would go like this...
You're a coward! Your fear of me, while justifiable, is pathetic and meaningless. If I desired you to be destroyed, you would be destroyed. The lives of these false Kree experiments are nothing to me. Know your place Ultron, or I will erase you altogether.- Thanos
Another moment that supports this theory could be the final moments of the trailers for Avengers 2. The part where Ultron says "There are no strings on me." could be a part of the film where Ultron thinks he's become successful in ending all life on Earth. For examples sake, lets say he launches all of Earths nuclear warheads. Right after launching them he looks down at the Avengers and reveals that its already over, and the missiles cannot be stopped. Him saying "There are no strings on me" could be referring to the idea that now that he's killed the humans, he is finally free of Thanos' grasp. The last string, being a connection to Thanos, has been severed and Ultron would truly in that moment be free.
Of course Im certain our Avengers would save the day! And since they do, and the humans/potential Inhumans of the Earth survive, Thanos still has a reason to come to Earth.
This is all just speculation, and we won't know anything for certain until Avengers 2: Age of Ultron hits theaters in May 2015.