The Great Dwarf is the patron god of dwarves, notably the Deldrimor dwarves. He was believed to be the creator of the dwarves, having forged them on top of Anvil Rock and taught the first ones to smith and fight. Though referred to as a single entity, the Great Dwarf is actually a collective consciousness created in a ritual which allowed the dwarves to better combat the Great Destroyer.
In fullfilling a prophecy told in the Tome of Rubicon, which tells of a titanic struggle between the Great Dwarf and the Great Destroyer, King Jalis Ironhammer invoked the Great Dwarf's power two and a half centuries ago in a ritual that transformed the dwarves into immortal creatures of stone, turning them into living weapons to fight the Great Destroyer and its minions, the destroyers. Initially, not all dwarves took the ritual – some notable dwarves who remained in flesh were Ogden Stonehealer, members of the Stone Summit and many other dwarves who were not present during the first ritual, but all were eventually forced to "become the Great Dwarf." The exact specifics of this transformation are not known – for example, Magister Ogden continues to work alongside Durmand Priory. His personality has clearly changed but unlike the other stone dwarves, he doesn't seem to be compelled by his alternate consciousness to battle the destroyers.