Sean McKeever scripts the return of one of Marvel's biggest threats in "Onslaught Unleashed"For years, mutants in the Marvel Universe have had to choose a path, whether it be the decision to follow the example of Professor Charles Xavier and his X-Men to try to work with mankind or treading down the path of Xavier's former friend and frequent enemy Magneto in an attempt to dominate humankind. Xavier, an omega level telepath, and Magneto, the mutant master of magnetism, clashed frequently and, in one of their most heated confrontations, a powerful evil was born. Known as Onslaught, the entity was inadvertently created when Xavier used his mental powers to wipe the mind of Magneto. By reaching into Magneto's mind, Xavier came into contact with all the negative emotions his adversary had been holding onto. Those negative emotions merged with Xavier's own dark side and a malevolent psychic entity possessing the powers of both mutants was born.

It took the combined forces of the X-Men, the Avengers, the Hulk and the Fantastic Four to stop Onslaught's initial rampage. In the process, the heroes nearly died, but Franklin Richards, the young son of the Fantastic Four's Mr. Fantastic and the Invisible Woman, used his powers to transport them to an alternate dimension. After spending a year in the wold known to readers as "Heroes Reborn," the heroes would eventually return to the mainstream Marvel Universe, but eventually, so would Onslaught.

In the aftermath of the "House of M" storyline, Onslaught was reborn, and once again it took the might of many of the Marvel U's most powerful champions to stop him. This time, however, Onslaught was not destroyed but imprisoned in the dimension known as the Negative Zone, where it's been watching and waiting for its next chance to strike. That chance comes this February when the four issue "Onslaught Unleashed" miniseries by writer Sean McKeever and artist Filipe Andrade begins. We spoke with McKeever about the project, which pits the might of Onslaught against the combined forces of the Young Allies and the Secret Avengers.

To Marvel fans, McKeever is probably best known for his recent work on "Nomad: Girl Without a World," the Nomad backup features in "Captain America," and the recently concluded "Young Allies" miniseries. All of these stories starred teenager Rikki Barnes (Nomad), a refugee from the Heroes Reborn alternate universe. In her home dimension, Rikki was the granddaughter of Captain America's original sidekick, Bucky, and grew up to become the modern day sidekick of her world's Cap. When she arrived in the main Marvel Universe, she adopted the identity of Nomad and continued her heroic career, both as a lone crime fighter and as a member of the youth-oriented super team known as the Young Allies.

The chance to continue to chronicle the exploits of the Young Allies, and in particular Nomad, was one of the reasons why McKeever accepted the "Onslaught Unleashed" assignment. "The 'Young Allies' series is over, but the concept lives on, both in the 'Arcade: Death Game' crossover that Paul Tobin is writing, and also here with 'Onslaught Unleashed,'" McKeever told CBR News. "With Rikki, I like that she's a character who feels like she's not in her world - and literally isn't. I think we all go through a period in our lives where we try to find where we fit in and we have to search for a role; whether it's in the world or when you move to a new neighborhood, a new job or what have you. To be able to grow that idea to a more universal scale is a lot of fun for me."

In recent installments of the Nomad backup feature in "Captain America," McKeever has been exploring and developing Rikki's relationship with Steve Rogers. That relationship will be an important story element in "Onslaught Unleashed." "Steve Rogers has come to see Rikki as a daughter figure and she's going to go through a massive trial in this story," McKeever revealed. "Rob Liefeld's recently revealed variant covers hint at what that trial is. So that's really the crux of the story. Rikki's going through all of this and Steve's unable to help her in a way that's satisfactory to him. I'm particularly excited to write Steve with his Secret Avengers. This series will truly be a shared miniseries between both the Secret Avengers and the Young Allies."

Rob Liefeld handles variant cover duties for "Onslaught Unleashed"Readers of 2006's "Onslaught Reborn" miniseries know the titular villain rampaged through Rikki Barnes' home dimension, but that connection is only part of the reason why McKeever wanted to pit the Young Allies and Secret Avengers against the evil entity. "There is that connection they have, but I will also be exploring something further," McKeever revealed. "I don't want to give too much away, but there will be a relationship - not in the familial sense - between Onslaught and Rikki that hasn't been explored before."

And it won't be just Nomad and Onslaught that share a connection in "Onslaught Unleashed." The story takes place in Colombia, where the Young Allies member Toro is originally from. "The setting is pretty important, because it's going to lend to the atmosphere of the story. It's going to be remote and dark. It's not happening smack dab in Manhattan, so the heroes can't just suddenly have everybody showing up to help," McKeever remarked. "'Young Allies' readers know that Toro was a child soldier in Colombia, so we'll get into why he was made into what he was made into. That will also deal with the other villain of the story, El Dragón, who was Toro's closest friend when he was a child soldier."

El Dragón is a new character that McKeever created specifically for this story. "He's a bit of a wild card and will be playing a spoiler role for the entirety of the story," McKeever said. "Not only do you have Onslaught, but there will also be this other evil in the form of a child soldier turned into a massive man-dragon."

The Young Ally Firestar and Secret Avenger Beast will also have significant roles to play in "Onslaught Unleashed." "They're both mutants," McKeever stated, "and because of that Onslaught will have a particular interest in them."

McKeever also plans for the other Young Allies and Secret Avengers to get plenty of screen time as well, with the writer especially interested in exploring the dynamic between the two teams. "They're the Secret Avengers. Nobody is supposed to know about them. So, in a word, the initial dynamic between the two teams is going to be awkward. There are going to be some sparks and some 'What The Hells,'" McKeever laughed. "It's really kind of cool to be putting these two teams together. You think of some of these characters like Moon Knight, then you think about somebody like Gravity, and its like, 'Wow! What would it be like for those two to meet?' You'll see that and hopefully you'll be surprised by some of their similarities."

Filipe Andrade has spent the last several months as McKeever's collaborator on the Nomad backup stories in "Captain America" and the writer is happy to be working with him on this higher profile gig. McKeever feels Andrade's style perfectly captures the tone of the story he's telling. "It's not quite an out and out horror comic, but it is going to be a lot darker than what people are used to from me," the writer revealed. "Not in terms of violence and death and destruction. There's just a dark atmosphere all around; a real sense of foreboding throughout the entire story. It would be like if you put a couple of Marvel super teams in the middle of John Carpenter's 'The Thing,' or something along those lines."

Despite the character's level of importance to the Marvel U, McKeever knows that Onslaught is over ten years old and has only really appeared on two occasions, first in the 1996 "Onslaught" event and then in the 2006 "Onslaught Reborn" miniseries. While that may mean many readers might not be overly familiar with the character, McKeever has made sure to keep "Onslaught Unleashed" exciting for both new and old fans alike. "The simplest way to explain the character is that he's the dark side of Professor Xavier and Magneto. He has their powers and he's a being made of energy. Currently, he's been exiled to another dimension where time runs differently and he's been waiting decades to get his revenge and return to the Marvel Universe. That's all you really need to know," the writer explained. "So you don't have to have read Onslaught's original appearances or 'Onslaught Reborn.' You don't even have to have read 'Young Allies' or 'Secret Avengers,' necessarily. This will be something you can enjoy all on its own."