Thought by some to be descended of some Human pairings with earth and water elementals, slyths are humanoid shapechangers found in small numbers throughout the Underdark. Another theory traces their origins to Aboleth experimentation with humans and derro, while one ancient legend holds that slyth were actually created by The Formless, who shaped a Gelatinous Cube into a humanoid and breathed life into it. Still another myth tells the same tale but maintains that Makiyaei created the slyths to tend to the deep places of the earth. Although their origins remain a mystery, slyths care deeply for the world of the Underdark and work to ensure that the many races and species that occupy it do not defile it. Slyths are few in number but strong in influence. They live long and make their presence felt in many ways.
In their humanoid form, a slyth appears to be a bald human, slightly taller than usual, with softer and more rounded features. Their skintones may vary in color, but brown hues are the most common. The slyth’s real form is that of an amorphous, oozelike creature whose body is midway between solid and liquid. In this shape, they resemble a puddle of mud, or syrup, or oil.
Slyths view themselves as the custodians and caretakers of the Underdark. At peace with the natural world, they believe it is their duty to help others interact harmoniously with the environment. Because they maintain amiable relationships with most races, slyths are welcome almost anywhere. In peaceful communities, they offer advice on animal husbandry, food cultivation, or foraging. In conflict-threatened areas, they act as arbiters. When feuding and raiding evolve into actual warfare however, the slyths refuse to take sides and simply leave. In times of open conflict, the slyths retreat into faraway niches that are difficult, if not impossible, for anyone without their alternate forms.