Aucturn

Aucturn was the name of the planet-sized egg or embryo of the nascent Outer God now known as The Newborn and was once considered the tenth and farthest celestial body orbiting The Sun in the Golarion System. It was completely destroyed when the Newborn hatched in 324 AG, breaking into millions of pieces that remain in orbit around The Sun, now known as the Gelid Edge.
Geography
Before its destruction, Aucturn appeared to be an organic, inhospitable world with a toxic, yellow-green atmosphere. Its soil was rubbery or chalky, and only mutated vegetation grew there. Its mountains resembled tumors, and its oceans were made of black muck. Its size constantly swelled and contracted, twisting its landscape. To outside observers, Aucturn's appearance was inconsistent due to a global magical illusion. Aucturn's orbit was filled with the wrecks of starships, supposedly sent by other planets to neutralize Aucturn during The Gap, which were a navigational hazard.
Despite Aucturn's mutable geography, it had several features that were relatively persistent. These included the Undulating Sea, a large ocean surrounding the southern ice cap whose shores hosted various settlements, most notably the Citadel of the Black, the Twisting Peaks, a stony grey mountain range that shielded the poppies of the south from severe weather, and the Chalkmounds, a smaller mountain range in the northern hemisphere made of a fragile stone capable of absorbing toxins, making the surrounding area less inhospitable.
Aucturnite
With the Birth of the Newborn in 324 AG, Aucturn shattered into millions of pieces, the debris forming a region known today as the Gelid Edge. Physical remnants of the planet are known as aucturnite and appear gray with an iridescent sheen. They are as hard as steel and possess psychic properties, and are in great demand to those wishing to turn the material into weapons or jewelry. Salvaging the aucturnite is complicated by the presence of the Midwives and other horrors who are drawn to the substance and will even track it down outside of the region.
History
Prior to The Gap, Aucturn was considered neutral ground between the Cults of the Elder Mythos, who wish to encourage and nurture the new god within the planet, and the forces of the Dominion of the Black, who wish to control it for their own purposes. During the Gap they fought one another, a war that ended with the victory of the Cults and the expulsion of most, but not all, Dominion forces.
In 324 AG, sensing the psychic cries of the unborn deity within Aucturn, the goddess Shelyn confronted Nyarlathotep in the skies above Aucturn and demanded he stop parasitising it. While Nyarlathotep defeated Shelyn, before he could land the killing blow, the god Zon-Kuthon came to his sister's aid. Together they banished Nyarlathotep from this reality and reversed the link between him and the fetus, forcing most of Nyarlathotep's power back into Aucturn's core. The nascent Great Old One acquired the power it needed to hatch, resulting in the destruction of Aucturn and the birth of the Great Beyond's youngest god, The Newborn.
Government
Aucturn was a lawless place where evil ran unchecked. Authority only extended as far as the individual leader's reach, and many places had no local government at all. The only laws that existed were built on power alone; the weak had no rights and were no more than slaves, food, or test subjects. Nothing was too depraved to be forbidden, and secrets were the most valuable currency.
Carsai
The most powerful leader in Aucturn was Carsai the King, a prominent cultist and suspected avatar of Nyarlathotep who ruled from the Citadel of the Black for millennia. Due to his relative reasonability and opposition of the Dominion of the Black that threaten the entire system, Aucturn was accepted into the Pact Worlds as a protectorate, and Carsai was even represented in some media as an antihero. He employed his right to speak, or send proxies to speak for him, at Pact Council meetings for several years.
Inhabitants
Orocorans were the most common among Aucturn's monstrous, vicious indigenous lifeforms, but were usually too drug-addled to pose any threat to others. Other native creatures included bryvaths, gugs, and shoggoths. Most native species preyed upon both of the major immigrant groups of Aucturn: the often-mutated humanoid worshippers of the Outer Gods and other insane people, who usually lived near the Chalkmounds or in sealed buildings. The latter needed to wear environmental suits when they went outside and or spent their time either getting high on drugs or focusing on dangerous goals that threatened the entire system. Other agents of the Dominion of the Black controlled remote facilities and avoided the attention of the cults, while protecting their secret lairs and contacting more Dominion agents from the Dark Tapestry. The Elder Mythos cults proved themselves resistant to the frequent Dominion attacks, and the rest of the Pact Worlds were content to let the Dominion throw its resources at a toxic planet on the fringe of the system. For millennia, Nyarlathotep used his temples to leech power from the entity gestating inside Aucturn's core.
Settlements
The largest city on Aucturn was the Citadel of the Black, home to the Pyramid of the Black Pharaoh, the largest temple to Nyarlathotep in the Golarion System. It was ruled by Carsai, who maintained a strained but somewhat cordial relationship with the other inhabitants of the Pact Worlds.
The second-most populated settlement on the sparsely inhabited planet was the circular tower-city of Amniek. It was located at the base of the polyp-like Gravid Mound, and was ruled by the Midwives, a group of 13 cowled spellcasters who knew of the Great Old One within Aucturn and fought Carsai who was leeching of its power.
Destruction of Aucturn
Many of Aucturn's residents saw the writing on the wall during the battle between Nyarlathotep and Shelyn in the skies over their homeworld. THose who had the means began to flee the planet. Any who stayed behind were instantly destroyed when The Newborn emerged and shattered Aucturn into millions of pieces.