I recieved a note from a troll yesterday, signalling the start of a series of events that'll bring about a Cataclysm in the world's biggest MMO, World of Warcraft.

The note invited me over to the Echo Isles off the coast of Durotar in Azeroth. It's one of the ancestral homes of the Darkspear tribe of trolls, but the tribe was ousted from the islands by a traitorous witch doctor named Zalazane, who began enslaving the population. However, the Darkspears, led by their leader Vol'jin, are fighting back, and preparing to take back control of their land.

Over the other side of the world, the gnomes of the Alliance are preparing a similar push back into their irradiated hometown, Gnomeregan. High Tinker Mekkatorque is pushing back into the city, with the aim of recapturing the surface to provide a home for the gnomes exiled by the treachery of Mekkatorque's chief advisor, Thermaplugg.

Both in-game events involve players of all levels, but only those between 75 and 80 will be able to take part in the final push to reclaim territory before World of Warcraft's next expansion pack, Cataclysm, is released before the end of the year.

Cataclysm will tell the story of the return of Deathwing the Destroyer, a massive evil dragon who's been hiding in a cave under the world since the events of Warcraft II. His return tears through dimensional barriers, ripping apart areas that have remained static since the game's original release, releasing rivers of magma through some zones, and unleashing floods in others.

The expansion will also make significant changes to the game's mechanics, introducing two new playable races -- the Worgen (who are essentially werewolves) and Goblins. It'll also simplify many aspects of the game's mechanics, removing little-understood statistics like attack value, armour penetration and block value, raise the level cap to 85 and introduce around 3000 new quests.

While there's no set release date for Cataclysm yet, it's expected to arrive just before the Christmas holidays. World of Warcraft's last expansion, Wrath of the Lich King, remains the the fastest selling videogame of all time, shifting 2.8 million copies in 24 hours. With 11.5 million players of the game across the world (more than the population of Greece), there's no reason to believe that Cataclysm won't perform similarly.