As the home planet to the julah, Yahzen is regarded as the oldest planet to have sentient life living upon it. Most of the Temple's teachings and even julah lore itself supports this theory, although some scholars (both julah and human) have posed other possibilities.
Long recorded legend purports Yahzen - and, more specifically, the inner sanctum of the High Temple - as the source of all spiritual life in the mortal world. The Void's presence is most heavily felt not only in the High Temple, but all across the planet. The average julah's sorceric abilities are also most powerful on Yahzen and its two moons for this reason.
Yahzen is a small planet with only one sea and few mountains. Most of the terrain is flat and wooded, with large swathes of meadows and green hillsides in between. The climate is mostly mild away from the poles by julah standards, and slightly warm by a human's. Between the fertile lands used for ancient agricultural practices and the "sparkling cities" that remain sparse on the landscape, Earth-based scholars have argued that the Garden of Eden in the Christian Bible might actually be a reference to Yahzen.
Geopolitically, Yahzen is akin to to Terra III and has no unowned land, although much of the land is still undeveloped after millions of years of julah civilization. Instead, the 100 Houses have long divided up the land into equal parcels that are self-governed according to global julah law as overseen by the planetary council. The exception for this is in the few city states that occupy the planet. These are self-governed as well, only by an elected body that cannot have more than one family member on its council. The capital and largest city is Armantha, and the holiest (and second-largest) city is Garlahza, where the High Temple is located.
There are two moons that orbit Yahzen, named Bah Zenlit and Sah Zenlit. (Lit: First Moon and Second Moon.) Bah Zenlit is the home of the Academy where talented youths are recruited to become the next generation of top politicians, healers, priests, and sorcerers. Sah Zenlit is the julah version of a pleasure moon, where multiple resorts exist. There is also a thriving industry around the seedier side of julah pleasures, and Sah Zenlit is widely understood to be the place to go for extramarital and family-unapproved liaisons. This reputation led to a regulated inkep industry that is ran by female matchmakers who work in tandem with resorts and hotels to assuage the hormonal needs of young women during one of their most volatile times of development. One curious thing to note about the moons is that, unlike other moons in the universe, both Bah and Sah Zenlit have atmospheres and terrain identical to that of Yahzen, and this can even be viewed when planetside. The only explanation that can be given - and the one officially in the history books - is that the ancient julah used sorcery to make them more mini-planets instead of moons.
Although a Federated planet, Yahzen has a special treaty with the Federation to run things the way they see fit. In exchange, they do not partake in the social aid that the Federation extends to all of its other citizens. Yahzen's economy is so old and stabilized that the citizens see no need to accept outside healthcare, education, and defense aid. That said, they do have one representative in the Federation Parliament on Terra III, a position bequeathed by the Grand Chancellor of Yahzen. Since julah live far longer than humans, the term period for this position is specially designated at 100 years instead of 10.
It is important to note that Yahzen and its moons are "closed" to humans. Immigration is nearly impossible for those who are not full or half julah and affiliated with one of the 100 Houses. Traffic is highly regulated, overseen, and enforced. Since humans cannot magically teleport, they must pass through an official checkpoint and have a cleared reason of purpose to visit. Tourism is non-existent. Human diplomats may live in the capital with their families, but these people are heavily scrutinized before being allowed admittance. The population of Yahzen is almost entirely of julah blood, and the culture itself reflects this xenophobic approach to existence. It's also how even the most progressive of julah prefer to keep things as well.