Iomis

Iomis was a planet in the Unknown Regions, the homeworld of the Kasci and an early member world of the Golden Empire.

Geography
Roughly 70% of Iomis's surface was covered with mineral and metal deposits, including bronzium, silver, iron, copper, tin, gold, and even the rare neuranium, among many others. Vast fields stretching for hundreds of miles on the surface of Iomis glittered due to the heavy concentrations of the metals, making the planet shimmer even from low atmosphere.

Of the remaining 30% of Iomis's surface, roughly half was given over to shallow, algae-covered oceans, with the rest divided among beaches, mountains, and the much-valued grasslands and other arable areas. Relatively little plant life grew on Iomis, compared to other systems with breathable atmospheres, but the algae covering the oceans thrived on carbon dioxide as well as water, recycling oxygen into the air and allowing life to develop.

Society and culture
Iomis was dominated by the Kasci, omnivorous metallic-skinned humanoids who evolved as second-level predators, beneath the resshet bird. When the Kasci evolved to sentience, they hunted the resshet birds into extinction and became the uncontestedly dominant species. With little arable land, the Kasci could not expand for lack of food supplies to support a large population. Kasci cities clustered near beaches on what arable land existed, using rainwater and careful irrigation to water their farms.

Kasci society was governed by a Prelature, with each independent city-state electing a Prelate to serve in the group, which acted as a worldwide legislature in a parliamentary system. After 91 ABY, the Prelate answered to a Royal Consul of the Golden Empire.

History
Kasci scientists theorized that the species had developed basic sentience no later than 15,000 BBY. The Kasci wiped out the resshet birds by 3000 BBY and began to develop lasting, stable city-states in the centuries immediately following.

By 413 BBY, Iomis had united under the Prelature, putting an end to various conflicts between city-states that had dominated the previous two and a half millennia. The Prelature briefly collapsed during a civil war from 196 BBY to 193 BBY, but was rebuilt afterwards with an identical structure.

At the invitation of Rin Sakaros, Iomis joined the Golden Empire in 91 ABY. The symbiotic relationship profited both immensely. Iomis sold its vast mineral and metal resources to the Empire at much lower rates than any other system could justify, given how much they had to spare, and the Empire introduced Repulsorfarming techniques and arranged the importation of freshwater supplies, which allowed the Kasci population to escalate several times over.

In 127 ABY, the Royal Institute of Military Science was established on Iomis. The planet was attacked during the Ssi-ruuvi Incursion, but successfully defended.