The military arm of the Martian Congressional Republic, one of the three great powers of the solar system. The MCRN is widely considered the most professional and technologically advanced military force in human space, maintained by a culture that views military service as both duty and honour.

The military arm of the Laconian Empire, equipped with technology derived from the alien shipyards of Laconia and significantly more powerful than any inner planet fleet. The Laconian navy is the instrument of High Consul Duarte's campaign to bring all of human space under a single authority.