The Ur-Quan Hierarchy, also known as the Hierarchy of Battle Thralls or simply the Hierarchy, is an interstellar empire created by the Ur-Quan Kzer-Za to manage their conquests that perpetuate the Path of Now and Forever. In our region of space, the Hierarchy consists of the Ur-Quan, seven Battle Thralls and at least four Fallow Slaves, including the Humans.
As the Kzer-Ah become embroiled in the Doctrinal War against the Ur-Quan Kohr-Ah, the New Alliance of Free Stars is established in 2155 and the Hierarchy begins to unravel as Battle Thralls start defecting or attacking one another.
It is unknown how this system has operated in past regions conquered by the Kzer-Za; they did not bring along the ships of any previously conquered races upon attacking our region, though it is possible that at least part of the crew of their Dreadnoughts originate from other regions. Also, the growing instability of our own Hierarchy near the time of the Doctrinal Conflict suggests that it might be dangerous for the Ur-Quan to keep Battle Thralls outside their direct supervision and control.
The Kzer-Za have a policy of modifying alien cultures to varying degrees in order to pacify them and make them useful to the Hierarchy after conquest. The extent of this most likely depends highly on the situation. For instance, the Kzer-Za were forced to take radical steps to prevent a nuclear war among the Thraddash — replacing Culture 18 with Culture 19 — while apparently leaving the Yehat clan system intact after both of those species became Battle Thralls. On Earth, they destroyed all Human dwellings, monuments and archaeological sites older than 500 years, including some of which the Humans were not even aware, apparently to forcibly uproot a culture they found troublesome and allow it to be completely replaced with a more Ur-Quan-friendly one. How often this was practiced for conquered worlds is unknown, though the Spathi claim to have undergone a similar process.
From February 2155 onwards, the New Alliance of Free Stars emerges as a counterweight to Hierarchy dominance, leading the Kzer-Za to threaten The Captain with the decimation of Earth should he continue to violate the Oath of Fealty.
The Ur-Quan Kohr-Ah are a rival superpower to the Ur-Quan Kzer-Za and both are engaged in the Doctrinal Conflict. On 17 February 2159, the Kohr-Ah begin the Death March to exterminate all races, be they members of the Hierarchy, Alliance or neutral.
Battle Thralls are essentially henchmen who obey Kzer-Za commands and act as agents to help subdue other species, and thus keep some degree of political autonomy and the freedom to travel through space. They are responsible for occupying Fallow Slave systems to ensure compliance and they are forbidden from fighting civil wars and conflicts against other Thralls.
Fallow Slaves are races that take the Oath of Fealty and then their homeworld is encased in a Slave Shield. They are maintain a Starbase by providing resources, crew and labor for the construction, repair, and refueling of Hierarchy vessels. Transport between the Starbase and the planetary surface is performed only under Ur-Quan supervision. Violation of the Oath is punishable by destruction of the shielded planet and thus the entire race.
As of February 2155, the Hierarchy consists of the Ur-Quan Kzer-Ah, seven Battle Thralls and four Fallow Slaves.