Asherati

From Syra D&D Wiki

The asherati are a thin, humanoid race living beneath the sands of the Pharis Desert. They have the unique ability to "swim" through sand, ash, or other loose earth, and are even capable of breathing normally under such circumstances. They can also make their bodies glow brightly, like lanterns. Their cities are all constructed below the sands, though they are fiercely territorial and are often hostile to those who pass above.

Though formerly unknown outside of the Pharis Imperium, knowledge of their existence reached the rest of the world after the Brightstone Heroes encountered them while trekking through the desert. Gurrard in particular has been trying to learn more about them, their society, and their remarkable abilities.