Portal

Here is what I have written up of the background, I'll finish typing it up when I get the chance. The rest is the rest of the ruins and the Cult of Unity and it's related city cults and orders.

I've added a couple references to things that seem like part of the world so far and removed other references to nearby cultures/races and the like that weren't really fleshed out to make it easier to adapt to the ideas of others.

Portal

History
Portal was built before any written history of any living race. It was ruled by the Akershule, who called it Asherayne. The Akershule ruled the city and the fertile lands along the bank of the River Jule for as long as the oral histories tell, well defended by their city walls and powerful magic. They did not try to conquer the surrounding lands or peoples, content to rule over their city state in relative peace, content to trade with their neighbors, so much of the city's history was peaceful. The Akershule warred when their city or farmlands were threatened or to prevent upstart barbarians from threatening their trade or the balance of power in the area (conveniently keeping any of the local cultures from becoming too powerful in the region), and when they did war they were formidable warriors, well equipped, trained, and disciplined while supported by powerful war engines and magic. For larger conflicts they used their considerable wealth to bolster their forces with numerous mercenaries. Never once were the walls of the city breached by enemies.

The Akershule knew many ancient magics, among them was the art of Gate Magic. They knew how to open gates to other places, and to control travel through these gates. [Several Hundred] years ago they opened a gate to hell and unleashed a horde of demons. The gate was in the part of the city on the west bank of the River Jule and that part of the city was quickly overrun by the demonic forces. The demons besieged the east city and spread outwards and terrorized the surrounding lands. Faced with a terrible alternative the peoples of the area united against the demons. Led by the barbarian hero Thakyr Ryn the unified peoples drove the demons back and broke the siege of Asherayne. The Akershule allowed the united armies inside their city and together with them drove the demons from the western city and back into their gate. The Akershule sealed the hell gate as best they could to prevent future invasions from beyond.

Weakened by the years of siege and war, their magical energies largely spent by the battles and sealing the gate, the Akershule were more vulnerable than any time before, and Thakyr Ryn knew it. Already inside the city walls he turned his forces on the Akershule and killed most of them in the city. The survivors and those outside the city fled to mountain keeps in the north while Thakyr Ryn took control of Asherayne and declared himself king, bringing in a new age. In the following years the Akershule, realizing their power was broken, entombed themselves in great crypts warded by their ancient magic and killed themselves. They left behind only strange inscriptions promising one day to return and right the wrongs of the past; no one knows if they mean the wrongs they committed upon the world by opening the hell gate or the wrongs that were committed upon them.

Thakyr Ryn established himself as ruler of the city and it's environs and renamed it Unity. He divided the city into sections, giving parts of it to all who took part in the alliance against the demons. He established cults and orders dedicated to the city and it's defense against the combined threats of the return of the demons and the Akershule. He succeeded in his lifetime of supplanting the loyalties of those who helped conquer the city with loyalty to the city over their own cultures and avoided factional wars. Upon his death he ascended to godhood and became worshiped as the founder of the Cult of Unity. The government and structure he created remain in place to the present day, though the many cultures who first settled the cities have all intermingled over the generations to make the city folk people of their own, distinct from the many cultures from whence they originally came.

The city kept its' prominence as a trading center and meeting point for the nearby cultures as boats from far away places traveled up the River Jule to trade at it's markets and the local cultures met there to trade or to negotiate on neutral ground. The gates remain a mystery, with cults to individual gates having arisen, though even those that worship them little understand their use. The city has become commonly known as Portal, with the name Unity being used to refer to the Cult of Unity founded by Thakyr Ryn.

The Demon gate still seeps evil, and the Western city has never been resettled. It remains a haunted ruin, prowled by things from beyond and those from this world who have no other place that wants them. Strange cults have taken hold in the western ruins, some dedicated to the gates that remain in that part of the city, and some dedicated to darker things, such as worship of demons from beyond or even the re-opening of the hell gate.

Geography
The city once straddled the great River Jule that stretches from the headwaters to the north down to the sea to the south, though today the city is only inhabited in the eastern bank of the river. The river creates a fertile river valley along it's banks that produce excellent farmland, though again it the eastern bank that is more heavily populated.
To the north are hills and a mountain range that stretch northeastwards, and to the west beyond are extensive hills that eventually meet another great mountain range beyond which is an massive and ancient forest known as The Green. The hills to the north and west are inhabited by Barbarian tribes and kingdoms, the ones to the north and east being more civilized while the ones on the west side of the river are more primitive and isolated from the rest of the world. The mountain ranges are inhabited by a fierce and violent race that frequently raids it's neighbors.
To the east are great arid plains inhabited by nomadic peoples and crossed by caravans from far away. Beyond that lies the desert that stretches to the foot of the mountain where the sun lives.
The River Jule winds it's way south to meet the sea. The coast is inhabited by peoples from the surrounding lands who came to make their living from the sea as well as people who came to this continent from the sea. Not far off the coast are a series of islands whose natives are masters at boat building and seamanship.

The East City: Portal
In ancient times under the Akershule the city was able to support a larger population than it currently can. Their advanced farming, superior infrastructure and administration, and the relative peacefulness of their reign resulted allowed a large population that the city today could never support, so that there are areas inside the walls that are sparsely populated and in disrepair, only nominally under civic control.

The city had two walled sections, an inner city and an outer city, on each side of the river. The inner city is fully inhabited and is where the government and prominent cults are based, where the best markets, tradesmen, and inns are, and where the well off live. Almost all of the buildings in the inner city were originally built by the Akershule, whose tall towers and ornate workmanship have lasted over the centuries, their engineering being superior to present day techniques. The Akershule did not open gates in the inner city, so they are all outside the inner walls, and though most all religions and cults are allowed in Portal only the Cult of Unity and its' associated orders are allowed temples in the inner city, all other cults have their temples in the outer city.

The outer city is much larger than the inner city. Since the city was built to support a much larger population than it can now sustain large parts of the outer city are largely uninhabited and only nominally under civic control. The outer walls, towers, and gates are garrisoned and maintained by the city guard, and so the neighborhoods next to the walls are relatively safe and inhabited, as are the neighborhoods adjacent to the inner city wall and along the major roads from the outer gates to the inner city. Much of the rest of the outer city is comprised of abandoned slums, where only the desperate who have no other place to go live. Periodically the town guard sweeps these slums in an attempt to evict all squatters, and though it is impossible to keep the entire city free of criminals and the destitute these efforts do keep the population of slums down to manageable levels. All gates and temples to non Unity cults are in the outer city.

The east city was once connected to the west city by bridges crossing the River Jule, most of which were destroyed in the war against the demons, only a few remain. These are guarded and access to the Western City is strictly controlled.

The West City: The Hell Ruins
The Western half of Asherayne is now a great ruin commonly called the Hell Ruins, the Demon Ruins or (less ominously) the Old City. Most of was ravaged in the demon wars and it has never again been reclaimed. There are still gates in the old ruins, as well as the hell gate. Even after the Akershule sealed the hell gate evil things have always seeped through it, though the ancient magics have held up against the invading hordes of demons that came through it when it was first opened. Many say the old magics that seal the hell gate are weakening, and that they soon will fail and the hordes of hell will again overrun the world – but then the doomsayers have been saying this for [Several Hundred] years now.