Gaelthane's Tarn

Surrounded by serrate peaks, an empty crater lake has, at its center, an unwelcoming island on which giant crystal prisms collide on the exposed bedrock, blinding all who look directly at it.
Deeper: The tarn was formed when Gealathen was slain and fell from the heavens. His massive bones are much of the near land’s superstructure, and his blood dried up the red sands that fill the crater.
Carvings on tarn’s edge show the isle of prisms being swallowed by a monstrous drake.
As summer peaks, the heat in Gealathen’s Tarn intensifies and awakens d20+4 sand drakes, ready to mate. The island is their nesting ground. When summer is over, they burrow and hibernate.
During spring and autumn, the dust nomad caravans pass through seeking the Penitent Oasis, a landscape on legs.
Without fail, some figure emerges from the masses each year claiming to know the location of the Penitent Oasis. They talk of hosts of diseased and maimed supplicants to the tarn with promises of restoration and cures. A full map and details of the Penitent Oasis can be found on p. XX.