All Federation species are elligible to join Starfleet, the armed forces of the United Federation of Planets. Non-members may be accepted for service on a case-by-case basis or as part of an exchange porgramme with another stellar polity.

The major threat species to the UFP are the Klingons, recently split into two (for all intents and purposes) distinct species. The Imperial Klingon States is a Triangle-based offshoot peopled by a genetically altered group who shun the denizens of the Klingon Empire, who have recently cured themselves of the so-called genetic virus and regained their original, ridge-browed physiotype. The IKS refer to themselves as "Fusions" and their ridge-browed bretheren as "Imperials". Other major threat species are the Romulan Star Empire and the Gorn Hegemony. Romulans are related to the Vulcans, while Gorn are large reptilian bipeds, like a small Tyrannosaur.

Minor threat species include the Orion Pirates, the Tholians and many others...