See the lexicon for the pronunciations of the names below.
Petralis is a former Imperial world. Considered a minor core world during the reign of the Empire, Petralis gained independence in the aftermath of the Cataclysm with the rise of Mel Teket the Great, the planet’s first divine monarch.
Petralis is heavily forested, though increasingly large swaths of land have been cleared for farming, in large part to support Petralis’ export economy. The population of Petralis is just over 1 billion, making such extensive farming operations unnecessary from the perspective of the local food supply chain.
The Petralon economy relies heavily on trade. The planet produces substantially more food than is required by the local population, most of which is exported to Zyar; and in turn Petralis imports many of the products manufactured by Zyar’s industrial base.
Zyar is a former Imperial major core world. The planet is marked by a set of massive rings, called ribs, that encircle the planet. The ribs—which are hundreds of meters thick—reinforce the planet’s tectonic plates, as well as provide a superstructure on which the rest of the planet’s urban structures are built. In fact, Zyar is covered in just one single city, though due to depopulation following the Cataclysm, substantial portions of the original are sparsely populated. Zyar’s current population is roughly 20 billion, though its sprawling nature makes an accurate census difficult.
The cityscape on Zyar extends in all three dimensions—and it extends so deep into the planet’s surface that many parts have no natural light at all. Informally, the planet is divided into two sections: the Overworld refers to the portions of Zyar that are high enough to have at least some amount of natural light, while the Underworld has effectively no natural light at all. The Overworld is considered prime real estate on the planet and prohibitively expensive for all but the most wealthy of citizens. The Underworld may as well be invisible to these people, and is the dumping ground for not just the planet’s industrial capabilities, but is also home to the vast majority of the planet’s population. Though the Overworld’s population is substantially smaller than could ever fill the planet’s surface, systemic inequality and political maneuvering maintain the planet’s cultural status quo, keeping the Underworld rabble in their place, far from the eyes of the Overworld.
Because Zyar has no natural landscape to speak of, the planet relies heavily on imports from Petralis. In exchange Zyar produces the vast majority of manufactured good in the known universe, having access to extensive natural resources, (literal) cubic miles of preexisting industrial infrastructure, and a large working population.
Zyar is generally credited as being the homeworld of the Zyrians, though, as a point of fact, it is not known where or how the Zyrians originated or whether they have a true homeworld.