Transformation of the Dwarves
The Great Dwarf's power is upon you all!
The Transformation of the Dwarves is the event in 1078 AE whereby the dwarven race attained its current, stony form. With it, the dwarves became living weapons, who existed solely to defeat their ancestral foe, the Great Destroyer.
The Transformation was prophesied by the Tome of the Rubicon, which foretold of a final battle between the dwarves' creator-god, the Great Dwarf, and his arch-nemesis, the Great Destroyer (now understood to be a champion of the Elder Dragon Primordus). It did not predict a victor, only saying that the dwarves would be "forever transformed" by this final battle.
When destroyers began swarming up from the Depths of Tyria, the dwarves set about gathering norn, asura, and Ebon Vanguard allies. After discovering the location of the Great Destroyer through the Scrying Pool, the dwarves sought out the power and guidance of the Great Dwarf. To that end, they required the Hammer of the Great Dwarf, the location of which was a closely-guarded secret of the dwarven Blackpowder clan, who had sworn an ancient blood oath to keep it safe until the day it would be needed.
With the Hammer in hand, the last king of the dwarves, Jalis Ironhammer, was able to perform the Rite of the Great Dwarf and transform the dwarves forever. With renewed purpose, the dwarves pursued the destroyers into the Depths, where they were able to defeat the Great Destroyer and delay the awakening of Primordus by half a century. Those that survived remain there to this day, fighting an eternal battle against the Destroyers.
Initially, some dwarves, such as Ogden Stonehealer and Kilroy Stonekin, were exempt from undergoing the rite. Similarly, the rebel Stone Summit dwarves (who once attempted to summon the Great Destroyer) were not present for the initial ritual. Eventually, all dwarves were made to undergo the rite—by force, if necessary.