Abridged Guide to Evil Wikia
"Even as he spoke the shimmered with mirages, Antigone’s eyes going wide as she saw a great winged dragon, its wings large as a city, slain by a great bolt of lightning. But the dragon came back in a great storm of flames, blighting the land around it."

The Drakoi were a race of draconic gods that inhabited Calernia long before the modern era. They were slain and turned mortal by the Titans in a war.[1]

The threat of the Drakoi led to the Dwarves, Goblins, and Drow living only underground. When the threat ended they began to walk the surface as well.[2]