Nephs were huge, docile flying beasts native to Dalos IV. They flew by generating hydrogen from water vapor and storing the gas in internal sacs. Increasing or decreasing the amount of gas stored allowed the neph to change its altitude. They had a long rudder-like tail and flat rubbery wings that they used to maneuver.
Immature nephs were used in the trophy chase, a sporting event popular on Dalos IV.