Known as the "City of Alabaster" or simply the "First City," Arkaster is the capital of Asgartha and the chief town of Caer Eidos. The metropolis itself, nestled between the peninsulas and islands of Sekent, Kemeri, Kuna, and Nisan, has more than 695,000 inhabitants, nearly a quarter of the entire Asgarthan population.

Arkaster's topography is divided between the Terraferma sites (which include the historic districts of Tesh Kanat, Kuth Kanat, Reykur, Vejaskira, Sonowen, and Jusaka, as well as the new district of Renkairi) and the lake districts built on stilts, the Permukaan (which encompass the districts of Arsenal, Gwyntewyn, Kladiver, Huskr, Porto Novo, Sjena, Felsenwel, Fosa, Kabatas, and Nafitera). The Karuna district is also entirely considered a lake district, even though it is partially built on a small rocky islet.

Two new districts - Usku and Koru - are officially under construction on the sea arm located between the peninsulas of Kuna and Nisan, but many years will still be needed before they can be inhabited by the metropolitan population. It should also be noted that Haven, despite its relative distance, is also considered a district of Arkaster.

The city has 695,648 inhabitants according to the latest census of 380 AC: 268,873 on the heights of the Terraferma and 426,775 on the Permukaan and other small islands of the lagoon.

The districts of the Terraferma are organized in tiers and levels, connected by wide concentric arteries or narrow lanes and alleys that steeply ascend the cliffside. Many of the dwellings have been carved into the rock; their facades, whether grandiose or more discreet, conceal labyrinths of corridors and rooms extending into the darkness of their stone framework.

Mostly historic districts, some dating back even before the city's founding, the Terraferma areas are home to some of the oldest families in the capital.

Located on the western shore of Sforafjord, Kemeri, like its twin slope on Kuna, is home to ancient troglodyte palazzos carved into the vertiginous cliffs. An epitome of bourgeois neighborhoods, Kuth Kanat features sumptuous residences as well as numerous temples. The entire area is interwoven with a maze of stone bridges, walkways overlooking the void, and levitating elevators connecting the fjord waters to the hanging gardens of the Yzmir Bastion. Indeed, at the summit of the rocky promontory sits the Kadigir, the Alteration School of the Yzmir Sorcerers. An impressive irrigation system channels water from a high-altitude lake, the Ayna, to the verdant terraces, before supplying the workshops of the Axiom Bastion below.

Facing the Kuth, the Tesh Kanat district is also built along an enormous cliffside. Like its opposite slope, it is shrouded in perpetual twilight, so numerous Kelon-powered street lamps have been installed. However, unlike Kuth, it is primarily home to old aristocratic families. It is said that Kuna is riddled with a multitude of underground tunnels and caverns, some of which plunge hundreds of meters down to the water level. The heights of the island, extending from the Tesh district, have been covered with large terraced properties. Over the years, these have become the most coveted residences for the wealthy population of the Peninsula. The pieds-à-terre of the regional governors can also be found here, though they rarely visit the capital.

Affectionately known as the "Forest of Temples," Reykur is home to numerous altars dedicated to the Eidolons. It is not uncommon to see small chapels nestled between two stone buildings, or lararia half-hidden at the end of a tiny, seldom-used path. The Asgarthans frequently make pilgrimages here to invoke and converse with the Eidolons for their assistance. Primarily residential, the district is often deserted during the day but comes to life at nightfall when its inhabitants return from their day's work. Reykur is overlooked by a sharp peak, the Acus, which is the highest point of the Peninsula. At the base of this rocky promontory stands the Wright Altiport, from which airships and aerostats service the entire Peninsula.

The neighboring districts of Vejaskira and Jusaka, due to their proximity to the Axiom Bastion, the Arsenal, and the artisan district of Gwyntewyn, are predominantly working-class areas. Most of the Foundry workers live here, as do the blacksmiths of the Arsenal. Walking through these districts, one can easily notice the prevalence of metal, from solid beams to various technological enhancements that each family has incorporated into their homes. Vejaskira and Jusaka are a maze of cables and pipes, intertwined with the network of streets. Day and night, one can hear the hum of wind turbines languidly spinning above the rooftops or feel the heat from chimneys towering overhead.

The island of Kuna is a massive rock that rises high above the lagoon level. It is steeped in history, as its presence convinced the Tumult Nomads to settle here, relatively sheltered from the overwhelming Tumult winds. Its western end, overlooking the Felsenwel, houses many of the Republic's centers of power, from the vast Kuningasplatz to the sharp spires of the Asterion. Like a colossal Mont-Saint-Michel, the palace of the Basileus dominates the bay, visible from almost everywhere in the city. This part of Kuna, being the administrative and political center of the Peninsula, is constantly under the joint protection of the Aegis and the Damocles.

Nicknamed the "Dormitorium," Sonowen is home to numerous scribes, copyists, and scholars of the Ordis. Every day, one can see them boarding the funiculars to the Altiport, to embark on barges that transport them to the Monolith. Like Reykur, it is a quiet district, far from the bustle of the Permukaan. However, it is pleasant to stroll through, as there are many small gardens arranged in individual terraces. On this side of the sea arm, the shore of the Nishaanfjord, otherwise known as the "Kerf Canal", is considered a sacred sanctuary. Indeed, it is along this cliffside that the tombs and crypts of the deceased are stored. Normally, it can only be accessed by water from the Huskr district, but some paths lead down from this district.

Overlooking the Kurung barracks, Renkairi initially housed the families of soldiers and guards who were stationed there, whether they belonged to the Aegis or the Damocles. However, the subsidence of Sjena has led to a gradual relocation of the inhabitants of this lake district to the stability of Renkairi. New houses are continually sprouting up in the district, which is expanding southwards and into the heights of Kuna. The creation of the Nafitera and Kabatas districts, along with the accompanying new urban dynamic, has caused an explosion of population density here. Indeed, many affluent families have settled in Renkairi to escape the hectic life of the Permukaan.

The isle of Yeni, located further north, is mostly uninhabited. If one looks northward from its steep, grassy slopes that plunge sharply into the two arms of Nishaanfjord, one can see the vastness of the Cierna sea. Only its southern part is occupied by Haven, a troglodyte monument co-administered by the Bravos and the Lyra. Both a place of residence and a museum of sorts, this citadel hosts members of both Factions during their visits to Arkaster. While one can admire numerous statues and frescoes of past heroes, Haven also features many workshops, halls, dormitories, training rooms, and the Sands —an open-air amphitheater where various competitions, athletic or otherwise, can be held.

Spanning nearly 200 small islets, most of which are artificial, interspersed by a vast network of 237 canals and connected by no fewer than 658 bridges, the Permukaan are now the beating heart of metropolitan life.

Thanks to Aerolithe technology, the Permukaan have been able to expand significantly upwards. It is now common to see buildings of seven or eight stories rising above the waters, connected by suspended bridges. The bases of the buildings are often shrouded in darkness, while the rooftops house the apartments of the wealthiest families.

The district of Sjena, wedged between the island of Kuna and the rocky foothills of the Kemeri peninsula, is almost perpetually shrouded in shadows, whether cast from the Acus or the Asterion. It is a poor district whose foundations are beginning to deteriorate: entire houses are sinking into the mud or under the water. Numerous stray cats live in this maze of beams and abandoned roofs. Recent efforts have been undertaken to stabilize this district, whose streets are almost always submerged, but the renovations are taking time. Residents who could afford to have migrated to the rehabilitated districts of Fosa or even Renkairi. According to legends, this district was initially modified by a powerful Alterer. Though his name has been lost to posterity, the waves here were turned to stone, creating an elevated area of solid terraces. It is said that the first houses were built on these waters. However, this historic district is no longer as popular. Indeed, aerolithe technology has enabled wonders, and the districts that have it, like Nafitera or Felsenwel, are now much more sought after. Sjena, due to the passage of time, is eroding and sinking into the sand. The families established here today are quite modest.

The districts of Nafitera and Kabatas were established during the reconstruction of the capital following the tsunami of 305 AC, under the direction of chief-architect Nanha Niski. Resolutely modern for their time, with wide thoroughfares and spacious streets, these districts served as experimental zones to persuade the rest of the capital to fully transition to Kelon technology. Some might say they lack the typical charm of the rest of Arkaster. Nonetheless, they function as a city within a city, clearly aiming to offer all the services available in the capital, but concentrated in one place.

Huskr is the departure point for the barges and gondolas that navigate the Nishaanfjord. The boatmen transport goods, visitors to the troglodyte cemeteries, or even to the distant Haven. The Ferrymen’'s Guild is headquartered here, and many boatmen live in a network of ships permanently moored side by side. Although the Monolith does not have a fixed position in the sky above Arkaster, it frequently hovers over this district to facilitate the ascent of officials living in Sonowen.

A quintessential bourgeois district, Karuna is home to numerous merchants and shipowners who reside there due to its proximity to the Porto Novo and Arsenal districts. Gradually, the island has expanded over the sea as maritime trade has developed. The inhabitants of Arkaster have taken to calling the part situated on the rocky edifice Karuna Altua, and the part extending at sea level Karuna Behera, although administratively speaking, the district is not divided.

Permanently shrouded in the steamy vapors of the Foundry, this hot and sticky district is home to numerous artisans, from clockmakers to carpenters, and stonemasons to blacksmiths. The streets of Gwyntewyn are crooked, hilly, and sometimes shift when the aerolithe platforms gently sway. Gwyntewyn is said to be the lungs of the Permukaan, as it seems to breathe with these rhythmic movements. Once the district of stonemasons, the sound of hammers and chisels has alas long fallen silent. The quarries that once dug into Kemeri have been closed and repurposed into residential areas.

The third district whose plans were sketched by Nanha Niski during the reconstruction, Kladiver is an extension of the Sjena along the Sforafjord. Over time, the arm of the sea has subsided, forming a narrow and deep rift. To counteract the gradual disappearance of this district, Kladiver was created. Unfortunately, its relative remoteness has hindered its development, further exacerbated by the notable abandonment of the development of Usku and Koru, which were meant to revitalize this part of the city. For now, Kladiver is little more than a stopover for the mistbreakers and all the boats heading up to the Cierna.

The new districts of Usku and Koru emerged from the waters only recently, at great expense of Alteration. These two areas, still under construction, were intended to provide new residential spaces to alleviate congestion in the old districts of the capital. However, following the launch of the Rediscovery Endeavor and the resources allocated to this grand project, the construction of these new Permukaan was abruptly halted due to budget constraints and lack of primary resources. It is rumored that certain fraudulent organizations have established their hideouts in these abandoned zones, using the cover of the half-built structures to conceal loot and goods. However, these rumors might merely be intended to deter visitors, who sometimes explore these quiet, lifeless places for sole leisure purposes.

The old harbor of Arkaster was destroyed by the tsunami of 305 AC. From its ashes rose Porto Novo and the Arsenal, with the former focusing on merchant shipping and the latter on Arkaster’s military vessels. Porto Novo is a bustling district, alive with the cries of fishermen and the constant loading and unloading of ships from dawn until dusk. Regularly, mistbreakers from the distant island of Suspira can be seen docking here. For several days, Kelon is transported from the docks to the depths of the Foundry, via an unceasing ballet of trains and wagons that travel inland to the island of Kemeri.

This is where the warships of Arkaster are built and stored. Civilians are prohibited from entering this district, especially since the construction of the first two heavy aerolithe vessels is currently underway. The Arsenal is an extensive complex comprising the military port and shipyard of its navy. Amidst the cranes, locks, and docks—whether dry docks, construction docks, repair docks, or berthing docks—large vessels constantly jostle for space, from fishing trawlers to Bravos drakkars, to battleships guarding the bay. But these ships are not the only ones occupying the area: an increasing number of flying ships utilizing aerolithe can be observed, ready to soar into the skies. Surrounding the Arsenal, numerous warehouses dot the Terraferma as well as the lacustrine districts; and factories operate at full capacity to manufacture the components needed by shipbuilders.

Its name originates from its grim past, when the bodies of victims of the Great Plague of 148 AC were thrown here, when there was nothing else in the vicinity but foaming spray and sharp reefs. Since then, Fosa has been home to the most modest populations, as well as cohorts of artists and performers who entertain the crowd in the Felsenwel, on the other side of the Grand Canal. However, the recent creation of the Nafitera and Kabatas districts has now revitalized this long neglected neighborhood. Moreover, despite its bohemian temperament, it is a very safe district due to the presence of the Kurung, the military barracks of Arkaster.

Bordered by the Bacchanalia district to the west, Felsenwel is a festive district that has always benefited from the aura of the Asterion. Considered more distinguished than the Bacchanalia, which is more popular in nature, the district has always focused on the Arts (Felsenwel is home to the lively Ruzzante district). It is a particularly popular place for affluent individuals, both day and night. The area near the Asterion is surrounded by a wall, and entry is only possible with a restricted permit. Indeed, Felsenwel is home to many chancellors and senators, constantly under the watchful protection of the Aegis sentinels.