Let's be up front about this. The Cataclysm was Deathwing himself. The events were the result of Deathwing's assault on the world of Azeroth - his eruption from Deepholm, his rampage through the Twilight Highlands, his summoning of Ragnaros into Mount Hyjal, the machinations of his minions. Deathwing, in all his rampaging insanity, was exactly what he claimed he was. He was the end of the world, and had he not been stopped, Azeroth would be no more. From the Twilight Highlands to the depths of Vashj'ir, the events Deathwing set in motion unraveled the world.
Let's look over the world, cast our eyes from the jagged peaks of Hyjal to the submerged depths of Vashj'ir, descend into Deepholm and then comb the deserts of Uldum for answers to the question - what did the mad dragon want? Why did his Twilight's Hammer erect their bastion in the Twilight Highlands, where the Maw of Iso'rath erupted from the very soil? The old gods seemed on the verge of their ancient goal, thanks to Deathwing.