 In "Expansion #2" the Lyran Empire was introduced to serve as a balancing factor in favor of the now-surrounded Klingons (facing opposition from the Federation, Kzintis, and Hydrans as well as the nuisance of the Tholians).The Lyrans border the Klingons on the far side opposite the Federation, and thus are natural enemies of the Kzintis and Hydrans.