The Yaddithians, Nug-Soth or Denizens of Yaddith, are a race of powerful magicians and brilliant scientists, hailing from the planet Yaddith.
General information
Although their world was ravaged by the Dholes, some of them escaped to other worlds, dimensions, or times. One of his inventions was a device known as "light wave envelopes," which were machines that could transport the minds of passengers through time and space.
They made their first appearance in "Through the Gates of the Silver Key", where Randolph Carter's consciousness occupies the body of one of them, the magician Zkauba.
They also appear in the Pathfinder RPG as one of the items belonging to the Cthulhu Mythos. Here, they appear as an ancient race of star travelers of great learning. They can live for thousands of years and hold spells in their minds.