The Great Wyrms were the third of the Immortals created by A-dui. They were formed from the rocks and soils of the wildest parts of Mire-Brissay, the hills and mountains, and animated by His breath. Given the limits of this material the Great Wyrms were created as large serpentine creatures, often as rough as the lands they came from.
As with the Sidhe, the Great Wyrms had a strong bond to the wild lands of the world. Unlike the Sidhe however they did not revel in the life of the world, but rather found awe in the lands themselves. They sought out places of splendor and might and made these places their homes, using their own innate power to imbue the lands with greater majesty. For them the solitude and unpredictability of nature was the highest perfection.
During The Age of Paradise the Great Wyrms had occasional contact with the other Immortals, but their interests lay far apart. And with the arrival of the Firstborn, they again had limited interactions, mostly with the Dragons. They taught the Dragons the power of the elements and the wilds and did little else. Draconic culture, as it exists, was influenced by the indifference of the Wyrms.
This indifference was also apparent during the War of the Immortals with most Great Wyrms playing minor roles, primarily when the War came to them. With the end of the War and the Accord of Withdrawal, the Great Wyrms faded away. To where is unclear. As is what, if anything, they wait for.