The Lyrans are a race of six-foot-tall cats, similar in appearance and temperment to a Terran lynx. Descended from a common ancestor they share with the Kzintis and Carnivons, the Lyrans run their empire like a feudal kingdom, with nobles (and their families) running planets, star systems, and sectors of space. There is no Lyran "national" symbol; the symbols shown is for the king. Each duke and each count has his own circular symbol with various emblems inside.

The Lyrans are allies of the Klingons, and are located on the opposite side of the Klingon Empire from the Federation. It is an alliance of convenience, as both empires border the Kzinti Hegemony, and there is no greater racial hatred in the universe than that between the two feline species. The Kzintis cannot abide the mere sight of a Lyran (and vice versa), so the Lyrans make an effort to remain on good terms with the Klingons. The Lyrans and Klingons jointly conquered the Hydran Kingdom (twice) and invaded the Kzinti Hegemony during the Four Powers War and again during the General War.

Lyran starships are twin-hulled "catamarans", which were easily converted into triple-hulled "trimarans" during the General War. Lyran warships include the Lion dreadnought, the Tiger heavy cruiser, the Jaguar war cruiser, and the Leopard destroyer. Lyran ships are armed with the same disruptors and phasers as Klingon (and Kzinti) ships, but instead of drone missiles, the Lyrans mount Expanding Sphere Generators as a defense against the masses of Kzinti drone missiles and Hydran Stinger fighters.