Rondo is a low life who travels to different space ports on back water worlds to gamble and drink. He is aware of his psychic powers and uses them to gamble and improve his odds but he he always loses it all again.
When Rondo was approached to join Project Telepath on Darkover he had just been thrown out of a gambling establishment and beaten. He then used his power to override the cheat safetys on the slot machines and made them all ring at once. Found by the Terran patrol and taken to the hospital Rondo was also approached by someone who wanted to use his special gifts to make money but he chose Darkover as the safer alternative.
Rondo is described as a little wizened man, 40s, tanned with a shifty look and blue eyes. When tested he had high telekinetic ability.