I'm surprised that this creature is actually mentioned in an old book I recently acquired: Hordes of the Abyss (p. 156 and 157). Apparently the 92nd layer of the abyss is a creature known as Ulgurshek, which is a Draeden, which lay dorment while the abyss formed around it. But while mentioned, the book does not go into detail about it. It does not provide any stats for it, nor even mention the Draeden creature type. Which is strange. If you're going to write a book about the layers of the Abyss, you'd think this unique creature would be worth a mention.