“How can you avenge the world, when the world was what turned against you?”
Kang the Conqueror, tired of losing to the many heroes of Earth, decided that a different route was needed. While face-to-face combat was his preferred method, he decided perhaps it was time for a more subversive way and influence the world down a path that would be more suitable for conquest.
It took time studying the timeline of this Earth without creating too many variations, but in the end, he found the perfect place: a moment in time where the heroes that he despised were the most mistrusted by the people they attempted to protect, where the US government attempted to control the superpowered population through law, and the superpowered community was split on how best to proceed, which inevitably would lead to conflict.
It was during this conflict, as the superpowered’s arguments eventually turned to blows, that Kang began to manipulate it. He plucked Super Adaptoids out of the timestream and reprogrammed them to only copy a few heroes' powers at a time. With these robots now on his side, he began to deploy them on assassination missions, targeting heroes that were alone or in small groups, and blocking the communication. Each hero killed and blamed on the opposite side, forcing the conflict to expand, becoming more violent and volatile.
In the climactic final battle of their so-called “Civil War”, Kang decided to force the conflict to an end. In the middle of New York, as heroes and villains fell out of portal, Kang sent another villain he had plucked from the timestream, a forgettable villain named Nitro, to explode, killing many of those in the general vicinity and leaving a massive crater in NYC. This attack led to the death of the Fantastic Four, Thunderbolts, many of the X-men and many former members of the Avengers. The deaths of both Captain America and Iron Man led the Resistance and Pro-Government sides to crumble, leaving a power vacuum that could easily be filled by Kang.
Following this, Earth was ripe for Kang’s rule. Using the deaths of the civilian population from the second explosion, the government began to crack down on all super powered beings, outlawing them and ordering them to surrender themselves to be depowered. Kang stepped in, revealing himself and offering his services to help enforce the rules. While many people were hesitant, especially since Kang had previously attempted conquest, Kang offered to sweeten the deal by revealing information of events that were yet to come. After an attempt by the Skrulls to take over that he helped repel, Kang helped to set up barriers around the plant to repel any future alien invasions. With this, the governments of the world submitted to Kang’s rule and thus began the Kang Dynasty. Using the Super Adaptoids as his own personal superhuman assassins, he hunted down many of the superhumans that he viewed could pose a possible threat to him, such Dr. Doom, Namor, Professor X, and many others.
Now, with most of all heroes exterminated, the few that remained did what they could to fight against the rule of Kang. The U.S.Agent, following the government's surrender, decided that it was time to found another team of Avengers. He searched for members who would have no problem crossing the line and eliminating Kang, and truly avenge all their fallen comrades. One of the first heroes John recruited was the Punisher, who had remained in NYC following the end of the superhuman conflict. He had somehow come into the possession of a War Machine armor and was now rarely seen without it. There were rumors that he was injured in the final blast and the armor was the only thing keeping him alive, but Frank refused to admit anything.
John hadn't meant to recruit Hawkeye, but she actually found him. Kate told him that she had been trying to group up with anyone who she thought could take down Kang and get revenge for her fallen Young Avengers comrades. She did mention that she knew that Kang could be killed, as she had seen it happen before, but clarified it involved time travel.
Many other heroes began to join this group of Avengers: Scarlet Spider, Quake, and Deadpool. For Scarlet Spider, joining was for vengeance and a chance to kill Kang for the death of someone he was close to. Quake joined because she wanted to do the right thing (and she had access to a series of S.H.I.E.L.D. safehouses that the team could use. Deadpool, having somehow become bonded to the Venom symbiote, wanted both vengeance for the deaths of previous hosts and just to kill Kang, but it was hard to tell who was in control anymore.
The final member was Ragnorak, a clone of the god of thunder. While many of them had heard/seen the original Thor clone killed at the final battle in NYC, apparently Tony Stark had made another one in case the original one fell, but kept it in stasis. After some debate the team decided to revive. Still believing that he was Thor, they chose not to let him know the truth and instead, began preparations for the confrontation with Kang.
This group of Avengers has an uphill fight against them. Not only do they have to fight against an enemy who has managed to conquer the planet, but has also managed to turn the majority population against the superhumans. Even if the Avengers succeed in defeating Kang, they must contend with a world who remains against their very existence. However, it has never been said the Avengers shy away in the face of adversary and well, if they couldn’t protect the world, they could be sure that they would avenge it.