Thauglorimorgorus was THE Purple Dragon of old. Thauglor ruled over an unbroken expanse of woods bordered on three sides by mountains, with a star-shaped lake in its center. This land would one day be known as Cormyr.
Iliphar, Lord of Scepters, defeated Thauglor in a feint of honor. This after years of the elf lord’s forces stealthily moving through the dragon’s demesne and slaying its lesser kin and vassal dragons.
Eventually humans settled the coastal edges of the elf lord’s realm. In time the elves retreated from the Wolf Woods.
After nearly 1500 years of rule by humans, what remains of Thauglor’s designs in Cormyr, aka the Land of the Purple Dragon?
More to the point, what did Thauglor do to that part of the Weave of all Magic that existed in its domain? After all, dragons and other powerful creatures have tampered with and even modified the Weave in the past, and Thauglor was truly a mighty dragon.
1. Perhaps Thauglor modified the Weave so that it would act as a shield protecting the dragon from the madness brought on by the King Killer Star.
2. Made it possible for the dragon to see and hear anywhere in the geographic region claimed by the dragon, as though it was all one enormous lair.
3. Learned to fall into the Weave and become a part of it, and perhaps become aware of and see the doings of magically gifted mortals, and sense and see/hear whatever is in the presence of magic items.
4. Inadvertently created a magical redoubt that resisted the worst of the Spellplague and so allowed Mystra to have a place to survive until her ascension a century later.
5. Maybe Thauglor searched for extradimensional pockets in the Weave, or created them outright, the better to portion out the dragon’s hoard and secret it away. This would have left things ripe for mysterious groups like the Sword Heralds to get to work hunting for the dragon’s treasures, and thus leaving plenty of handy extradimensional safeholds in the process (these exist in modern day Cormyr, and are the subject of much conjecture and debate).
6. Made it easier to cow the minds of lesser dragons.
7. Created pockets of raw magical might. Something that could be called upon when Thauglor faced one or more hostile dragons, or several mages of power.
8. Smoothed out the rough edges in the Weave, untied any Weave tangles, and ensured areas of dead magic were few or otherwise remote and walled off so no spy could use them to hide from the Dragon.
9. Left Weave Whispers and echoes of his commands and instructions to his spawn and to his agents, that can be heard in specific places whenever the right spell or spells are cast in that area.
10. Turned it into the ultimate phylactery, and tied it into the blood of Iliphar, and later the blood of the Obarskyrs. So long as the Weave exists (no matter how diminished) and mortals of Royal blood draw breath, Thauglor can never truly die.