Caldein is a Malsuth Crown World in the Kingdom of Malsuth. It has a population of 2.7 billion Malsuth, all concentrated in the planet's fortress cities.
The environment of Caldein is generally terra-like. It is hot and wet near the equator, deserts above and below the equator, and gets cooler and more varied the further you go up.
What sets Caldein apart however is the outright hostility of what is in its environment. Predators, even small insect-hunting, low-tier carnevores have incredibly strong armour plating on them, teeth and claws with evidence of organic metals in them, some with poison strong enough to kill several dozen full-grown Malsuth. Higher up in the food-web, with high-tier predators you begin to find armour plating which can resist limited small-arms fire and claws that can rip through thin armoured vehicle armour. All domestication attempts in all forms have failed. The hostility in the environment has led Malsuth scientists to beleve that Caldein was a former test-site for a precursor race for weaponized animals.
What herbivores have survived on Caldein are mostly incredibly small. They eat ground-cover plants for sustinence and live in burrows deep in the soil layers with hundreds of other herbivores. They have sharp, natural claws to defend themselves if an attack happens by whatever, and usually attack en-masse as a pack.
Unlike the fauna, the flora of Caldein has ignored and instead thrives out of of what can be considered a biological arms-race that is being conducted by the species of Caldein. Overgrowth is common in Caldein's forests, and this has led to decomposers in Caldein to have to become incredibly effective at reducing dead plant waste on the forest floor.. Caldein's forests that experience dry-steads suffer from incredibly wide-spred wildfires in late spring, summer, and early fall from the amount of dead plant matter, which does help keep the forests fresh in nutrients and clear for new growth to take over.
The economy of Caldein is entirely self-sufficent, with the Fortress-Cities of Caldein being able to supply themselves. Mining, farming, lumber, manufacturing, all of that is done in the cities themselves with underground greenhouses being the norm. Trading between the different regions of the planet is done via air routes, as anything on the ground (Even underground) would be unsafe due to the wildlife on Caldein. Most manufacturing is light industry to supply civilians, but the older fortress cities on the world (primarily Caldein Vale) have larger heavy manufacturing centres and produce a noticeable fraction of the Empire's small-arms needs, and produce all the small and heavy arms needed to supply the city militas of Caldein.
The cities of Caldein are fortress cities, maintaining the last functional city walls in the Malsuth Empire. They house anywhere between 250,000-40,000,000 people in their walls. They are all self-sufficent in food production, and trade with other cities for regional resources they don't have access to. The walls they have are generally lined with Glacier starship armor, and have Projectile Cannon Turret PD on the bastions for use against flying wildlife. Spread throughout the wall main-sections are Anti-Tank Guns and High-Explosive Tank-Destroyer turrets to fend off larger ground wildlife.
Along with Barbers Sun, and several other worlds, Caldein is one of the few worlds of the Empire directly administrated by the Crown. Instead of being part of the feudal customs of the Empire, Caldein instead has locally nominated and elected administrators from every city who are directly loyal and subservent to the Crown. This leads to Caldein's loyalty near-guaranteed to the Monarchy under most circumstances, because it is far easier in terms of opinion and in technical processes for the Crown to replace a city administrator.
Caldein has a unique military culture in which most people on the planet, at the age of 16, are inducted into the reserves for training. This military culture is an offshoot of the military culture that the Malsuth Empire has in general from before the Malsuth were spacefaring as a species. Most of Caldein's adult population is in the reserves until the age of 60, ten years longer than the drumming out age for the rest of the Empire of 50. Despite this, Caldein does not maintain a larger active armed forces than the Empire itself, instead relying on city milita to defend its fortress cities.
Caldein was discovered in early 1,405 B.C.E by a civilian colonization ship, it was an uninhabited world with a ruined stargate in orbit of the last planet of the system. Caldein itself was ignored for the most part until the 1440s in which the first working stargate connection was built in a different orbit than the ruined stargate, several thousand kilometres closer to the parent star. This unlocked colonization and shipping to Caldein, in which the first colony was setup in early 1,445. This began the first Wave of Expansion for the Malsuth Empire, in which STL ships were dispatched to nearby stars to colonize and expand to.
The first colony on Caldein was a small outpost of 340 people, mostly civilians, called Neo Malsuth. It lasted for exactly five months with a slowly shrinking population due to animal attacks until it was finally wiped out during a migration period of the wildlife on the planet. This resulted in a military expidition to determine the cause of destruction, which concluded the overly-hostile environment was the cause.
The second colony was a larger outpost of 535 people, with a company of marines being sent to escort. The outpost itself was called Caldein Vale, after the geographic region it was settled in. This outpost was settled in a small vale with a stream running through the valley. Basic fortifications were setup before civilians were landed, with heavy military equiptment setup at chokepoints. When civilians were landed, they were instructed in military drill to assist in colonial defense. Although deaths due to wildlife were common, the colony thrived after several years when the valley itself was claimed and civilized for Malsuth use.
This spurred Malsuth colonization of the planet with systematic military campaigns to claim and civilize easy to defend locations on the planet such as plateaus, passes, the base of mountains, peninsulae, islands, ECT. The military labour to wipe out the hostile wildlife was generally from batalions from Malsuth (System,) until the planet could sustain its own recruitment. This led to a Caldein military culture which survives to this day.