It is unclear if Qo'noS served as the capital world of the Klingon-Cardassian Alliance or merely the Klingon portion of it (or if the Alliance had, in fact, a centralized location of government).
Star Trek: New EmpireEdit
In Star Trek: New Empire, Qo'noS was covered by large tracts of desert, giving it a reddish-orange glow as seen from a distance. This condition may have been the result of conflict with the Terran Empire.
In the 2370s and 2380s, a war of attrition with the Imperial Union of Planets depleted Klingon military forces, leaving Qo'noS relatively defenseless. In 2385, as Imperial Starfleet forces led by the ISS Arcadia approached, the Klingons destroyed Qo'noS using nuclear subterranean explosives, a Pyrrhic measure in order to prevent occupation of their homeworld. This move was seen as reminiscent of Japanese resolve during World War II, to prevent foreign powers from setting foot on their soil in conquest.