The Klingon empire..... .......almost joined the Federation but left as a result of a military coup which ended their brief experiment with democracy. Planets conquered by the Klingons either joined the Federation or became part of the Klingon Neutral Zone . The series "Humans" and "Space: Above and Beyond" are set in the Star Trek universe. The AI War was later referred to as "world war three" and was an attempt by the Synths to increase their number. The Klingons are really Augments, genetically modified humans who left Earth during the Eugenics War. These Augments conquered a number of planets and created the Klingon empire. Elements of the conquered culture's religions ended up becoming adopted by the Klingons. Vulcan Intelligence deliberately started the Earth-Romulan_War . This was done by providing Earth with Vulcan technology. When Earth ships started exploring and setting up outposts near the Romulan border, the Romulans attacked ...