What exactly is the "Age of Onslaught"

The "Age of Onslaught" is a fan-fic line, set in an alternate world where Onslaught rules North and South America.

Fan-fic?

Fan fiction. Stories told by the fans of the characters rather than the creators, with no affiliation to Marvel whatsoever.

So the "Age of Onslaught" is an alternate reality? What's that?

It is a reality outside of normal Marvel continuity. A reality where the outcome of a single event was different from that of the established reality, thus spawning a new series of events, forever setting the "alternate" world apart from the original reality. In this case it was the death of Magneto that caused Onslaught's ascension.

Onslaught?

Onslaught is/was the "Dark Side" of Professor Charles Xavier, otherwise known as Professor X. When Professor X wiped Magneto's mind clear, a portion of Magneto's own hatred from humankind crept inside the mind of Xavier. Eventually these feelings or anger and hatred took the form of a psionic being known only as Onslaught. The being, born out of the combined minds of Xavier and Magneto, then set about the task of eradicating the human race, killing most of Earth's heroes in the process. Eventually Onslaught himself was vanquished, with Earth's heroes safely in another pocket dimension known as the "Heroes Reborn".

I take it that isn't how things happened in the "Age of Onslaught" then?

No. In the "Age of Onslaught" Onslaught emerged at a much earlier stage, and with no one to oppose him he easily secure his rule of America.

What was it that caused this reality to come about?

The death of Magneto twenty years in the past.

In this reality, the mutant known as Legion suceeded in his goal of assassinating Magneto in the past, thus creating this world in order to replace the "real" Marvel Universe.

But wait a minute, if Magneto's dead how can Onslaught have been created? You said he was a combination of Xavier and Magneto's minds...

Well I'm not wanting to give away too much here, but let's just say there is a way.

So this is basically the same as Marvel's "Age of Apocalypse" story, but with Apocalypse replaced by Onslaught?

No, it's not the same. If it were there'd be no point in telling these stories, now would there?!

So what happened next? Did Xavier form the X-Men to battle Onslaught? Did Bishop remain on this world? What about Apocalypse, did he still resurface on this world?

Hey there! Slow down a little. No Xavier did not form the X-Men. After being left powerless and crippled at the hands of Onslaught Charles disappeared for many years.

So who formed the X-Men?

Give me a chance to answer here! Okay, well, to answer one of your other questions, yes, Bishop did remain on this world. Like in the AOA, Bishop's mind was unable to handle being shunted off into another reality, and he roamed the world for years until a very powerful mutant (whose name I'll not mention here), repaired his fractured psyche.

Bishop then set about gathering this world's X-Men, searching for them around the globe.

Why was Bishop not erased from existence like all the other X-Men?

Because Bishop is a space/time anomaly, and exists outside of the currents of the timestream. The other X-Men do not.

Okay, so you've answered two of my questions. What about Apocalypse?

Apocalypse does, indeed, emerge on this world, but has chosen to remain in the shadows, biding his time until the opportunity to strike Onslaught presents itself.

So who are the X-Men?

Ah but that would be telling! You'll definitely see some regular faces along with a few new ones, and older characters long since forgotten. We're basically draining the X-Men well dry here!

I just looked over the main page. You've got some interesting titles on offer, could you explain a little about them?

Okay, well, here's a short description of each title, listed alphabetically;

ASTOUNDING X-MEN tells the tale of Legion and his band of X-Men as they battle Onslaught's prelates.

BISHOP:THE LAST X-MAN focuses on the founder of this world's X-Men. The only man who knows the "truth" about this world.

In the EXTRAORDINARY X-MEN, Havok and his band of X-Men battle against the mutant-hunting sentinels.

In GAMBIT, the world's greatest thief, is hired for a very...unusual job.

In MUTANT X we find out the true fate of Charles Xavier as he meets the Manites!

QUICKSILVER & SABRETOOTH. What do the duo of Quicksilver and Sabretooth have in common? What is their shared past?

In TEAM X 2000, the members of Canada's Weapon X program reunite to infiltrate a Sentinel Processing Plant in Germany.

WOLVERINE & SHADOWCAT, two of Onslaught's highest-ranking prelates, return to battle their former allies, the Hellfire Club and the Hellions!

X-POSSE tells the tale of Meltdown and her gang of mutant rebels as they take it to Onslaught's forces.

X-MAN. The adventures of Scott Summers (Cyclops), his wife Madelyn and their baby son, Nathan.

X-MEN UNLIMITED is the third "core" X-Men title, and focuses on Rouge and her band of X-Men as they battle with the anti-mutant Right organisation.

In a flip-side to X-Men Unlimited, X-TERMINATORS showcases the Right's anti-mutant underground network as they attempt to eradicate all homo sapiens superior.

There are also two "non-mutant" titles in the line that focus on this world's remaining "metahumans". The first title is "THE FLIGHT", which focuses on North America's Human resistance.

And the second is "THE SPIDER-MAN", a modern-day Robin Hood, robbing from the rich to give to the poor. Or, in this case, Onslaught's prelates and the Human Resistance movement!

Wow that's a lot of titles! It sounds very interesting, and I'd like to join up and help write one of the titles. How do I go about this?

Well, if that's the case, email the AOO EiC, Benn Vallely, with your ideas. Include a short issue synopsis and a list of characters you'd like to reserve. He'll get back to you as soon as possible.

So I can reserve any characters I want?

With a few exceptions. Those characters starring in their own titles (Quicksilver, Sabretooth, Gambit, etc.) are not likely to appear in any of the other titles. Also certain characters that are instrumental to the line as a whole are "out of bounds", but I'll get into that only if need be.

Also, make sure that the characters you want to use would be likely to appear in this reality. Bloodhawk of the X-Men 2099 wouldn't appear in this reality, as he was born many years in the future. The same goes for characters like Cable and Dark Beast. The only time-displaced character in the line should be Bishop!