The population, consisting only of resident Avernites and not Imperial traders, is large for a province of its size in the Kingdom of Avernum, but still smaller than the Eastern Gallery or Great Cave. There are an estimated five hundred thousand Avernites living in Upper Avernum.
The economy of Upper Avernum is absolutely essential to the Kingdom of Avernum. Imperial merchants, paying a small fee to go through Fort Emergence, either trade goods with the merchants there, or continue on to Portal Fortress, and a few as far as the Tower Colony. Spices and gemstones from Vantanas, ores and food from Valorim, textiles and lumber from Aizo, and manufactured goods from Pralgad come to these three places, most often Portal Fortress or Fort Emergence, as there is a fee to use the Surface Portal to get to the Tower Colony, and there the goods are traded with Avernite crystals and ores. The traders here then send a small portion of the goods to New Cotra and New Formello, while the majority of the goods are taken down the Surface Portal to Tower Colony, where merchants from all over Avernum trade for them.
Discovery and Settlement
Upper Avernum was discovered during the Empire-Avernum War, but due to the war no attempt was made to colonize it. Once the war had concluded, mages in the Tower of Magi were able to construct a portal linking the two cave systems. This was kept secret from the general public for a time, while the army went up and built the basic framework for two essential forts, Portal Fortress protecting the Surface Portal, and Fort Emergence protecting the way to the Surface.
Before they could finish however, news leaked as the the work being done in the Pergha mountains, and King Micah had no other option but to let through waves of screened settlers, volunteers, and colonists. Portal Fortress became a strong city for the settlers, and many Avernites eager to be near the Surface went to For Emergence. Meanwhile, two non-military sites, New Cotra and New Formello were set up to the north of Portal Fortress. The Vahnatai, supposedly eager to see the Avernites off to the Surface, established the settlement of Ghikra accross a lake from New Formello. Ghikra was actually a base for Rentar-Ihrno to create the Plagues of Valorim.
Surface Exploration and Reconciliation
Soon after the construction of Portal Fortress and Fort Emergence, the First Surface Explorers were selected by the Crown from Unspecified Services to explore the Surface and make contact with the Empire. They were relatively famous adventurers in Avernum beforehand, and they were expected to be met with great successs. All of them, with the exception of Tucker, died in southern Valorim. Worried, Anaximander soon recruited less experienced adventurers, the more famous of the two parties, and sent them into Krizsan Province.
The Second Surface Explorers one by one managed to destroy the sources of the Plagues, from slimes, to cockroaches, to Troglodytes and Giants in southern Valorim. In northern Valorim, they destroyed the Tower of Shifting Floors and Crumbling factory, where the Plagues of Golems and Alien beasts were respectively being created. Then, the Surface Explorers identified the Vahnatai as the creater of the Plagues, causing the Vahnatai to evacuate Ghikra. In Blackcrag Fortress, the Surface Explorers met with Empress Prazac I, and between Anaximander and the Empress, they negotiated a deal for Provincial Avernum. After removing Rentar-Ihrno from Valorim, at the cost of Erika Redmark's life, the Kingdom of Avernum gained Provincial Avernum.
Cult of the Sacred Item
For a time, the Cult of the Sacred Item held caves in the northern extreme of Upper Avernum, connected only by a river. Here, they raided settlements across the Kingdom of Avernum, making minor thefts of magical items via portal. The Cult eventually stole the Orb of Thralni from Fort Emergence. Enraged, Anaximander of Unspecified Services tasked the Surface Explorers with the recovery of the Orb. The Surface Explorers were forced to go to Seles, who temporarily redirected the Surface Portal at the Portal Fortress to the Cultist Caves. The Cultists were, for the most part, destroyed and scattered to the winds, the northern caves being abandoned.