Saxum

The rock dragon Saxum is a powerful immortal creature that lives in the Pindus Mountains. He is said to be the lackey/pet of Nedra the frost lich, and seems to do her bidding for the most part. It is claimed (by Larry the Immortal) that Saxum is also the guardian of the Fountain of Youth, with Larry having bested him in a game of Pebblesmash in order to gain access to the Fountain.
Saxum was also the destroyer of old Hyperion, having somehow gained access to the interior of the domed city (it was never discovered how), he destroyed the inner supports of the outer dome wall, collapsing the protective layer and unleashing the cold, and more prominently, the rapidly oncoming Aether Storm, on to the unspecting city populace. This even became known as The Saxing, and saw many of the residents of the city fleeing in a mass exodus (to eventually found New Hyperion). Those few that remained either became Aether Zombies, died, or hid in the remains of buildings and survived the onslaught of claw and storm long enough to later rebuild the palace and observatory.
Saxum in the modern era is more myth than legend. Some say maybe he died. Others say he still slumbers in the mountains, waiting for the next Larry to try something foolish...