A long time ago, there was this place called Sios. One continent, large oceans. Then, beings from another world came, splitting the continent up, causing massive damage, seperating the peoples. This was a period of time called The Sundering.

From there, each new continent developed its own culture and identity.

MAWs were created, along with Airships.

The Airships were pretty much the only way to get around to the different continents.

In MW:Zero, the Mavericks (a group of pirates mostly piloting ManDrake MAWs)had taken over an island (Mostly referred to it as Zero Island or Maverick Island by the members of the Mobile Weapon Forums), and from there took over most airships.

Eventually, a pilot in an Avenger managed to defeat them, freeing Sios. His name was not given, unfortunately. This was only a trailer, after all! However, one of the first members of the MW Forums, Captain Zocra, who goes by Zocra Erriyu on the Facebook forums, was honored by being given a cameo as an experienced pilot who gave you some tips on MW:1; Zocra in MW1 could possibly be the pilot from MW:0

Then, over on Acero Isle, Ron raises Callisto. He was a famous pilot in his youth (So Ron is also a candidate for the MW0 pilot.). Callisto becomes the engineer of the island. Billy Barrage's dad dies in a cave-in at the Lazlo Mines, his mom (a bounty hunter) seems to disappear. Jin (the main hero, although the name is changeable) is also raised by Ron and sorta by Callisto; Billy is a good friend to Jin. Jin, Billy, and Callisto are the younger MAW Pilots on the island, and very good ones at that.

After a series of adventures on the island, facing many monsters, etc., Jin and the party see Ron kidnapped by Ariel Highwater, an Imperial Commander.

Jin fights Ariel in her Serra Superion, a very powerful MAW (Mobile Adaptive Weapon, a small mech); Jin is piloting his Avenger MAW. No matter the outcome (a win, though hard to get, gives great rewards.), the outcome reveals their destination: The Imperial City.

In MW:1 Premium, this is where the party meet Laura Livingston, a historian researching an ancient civilization. They search the Ancient Ruins of Acero Isle, eventually fighting an ancient guardian and turning on a teleporter. Very little else will be revealed until the next installments of the Mobile Weapon Series at Leonard's request. Suffice it to say that this teleporter won't do anything without the others turned on, and will be a very powerful item and plot point in the future.

In Premium, the characters also meet Cyphus, who is the leader of the Hunter's Guild. He gives the party quests to take out certain kinds of monsters. There's a secret store at night where incredibly strong weapons can be found.

Drake, an Airship owner, gets everyone to go into the Tidal Caves to find parts that had fallen off his airship, the only way to get to the Imperial City. They eventually fight Crazy Jack, a pirate who had lost himself in there, get the awe-inspiring Y&S Suppressor and TY Thundershot guns, the parts, and go back to Drake.

From there, Jin and Crew fly out to the Imperial City on Drake's Airship. MW2 will pick up from there.

Over on Acero Isle, the Bandit Lord stole parts from Ron. Somebody, presumably Callisto, Jin, and Billy, are recruited to go take him down. A mysterious Gear Fly Pilot is also recruited, and the parts are taken back.

As the main characters are never seen, except for their MAWs, it is assumed that this game took place sometime during MW:1, as (the presumed) Jin already had an Avenger MAW, but Ron was not yet taken by the Imperials. If it was not Jin, then other MAW Pilots must have been hired by Ron.

From MW:LotGD, though it's not canon, there's some info. For example, there was a Great War between the Drask (People of Al Amraan) and the Imperials (Of the Empire.). Both are located on Terra, the eastern continent. As this is a text-based game, and is largely non-canon, there is not too much that can be directly applied as Sios History. If more is found, please post it here.

Awesome!