Trill initiates were those of the Trill species who joined an initiate program in order to train themselves for potential joining with a symbiont. The initiate program consisted of an intense series of exams and evaluations, both mental and physical, that were designed to eliminate all but the most suitable and dedicated applicants. Over five thousand candidates qualified for the training each year. On average, only three hundred symbionts, annually, were available. As such, it did not take much for an initiate to be knocked out of consideration. Only the best and brightest were joined. (DS9: "Dax", "Playing God")