The tropical world was established as a major spice-processing center by the criminal kingpin Zavval the Hutt. Realizing that he would need slaves to labor under hellish conditions, the wily Hutt chose not to purchase them. Instead, he came up with a way to create slaves.

His lieutenants were of the t`landa Til species and could therefore emit a natural harmonic that stimulated the pleasure centers in a subject's brain. Lured by the trappings of a pseudo-religion, hundreds of spiritual seekers went to Ylesia to experience this wave of bliss, which was touted as "the Exultation".

The slaves soon became addicted to the sensation, making them easy to control. Living in ascetic colonies, they spend their days refining the spice and their nights are spent scrapping parasitic fubgus from their callused hands and crowded into the Alter of Promises, where the t`landa Til "preists" issued the rapturous Exhultation.

After a long year of sweat and toil the docile proseltytes were shipped off to slave camps and pleasure houses, while their positions were filled with new converts.