Bastion

Hidden below the surface, protected by the facade that is The Sink, lays the largest city on the continent of Lasair. The true home of the Dwarfs to which no outsiders may visit, the hidden heart of dwarven culture and duty, and a bulwark against invaders from deep within the world.

Heart of Dwarven Culture

While the public face of the dwarfs is the quarry of The Sink and the stonecutters that work there, they keep a private face for themselves within the deep city of Bastion. Founded long ago, around the same time as the dawn of the Imperial Era, Bastion has been the home of Dwarfs on Lasair for thousands of years.

History of Bastion

When the earliest dwarven arrivals began digging into The Sink, they discovered rich veins of metals hidden below the granite nearer the surface. As these veins were mined out, processed, and stored, the dwarves excavated the spaces more completely. As they created rooms, buildings, and larger spaces, they began to organize the new city and made it into a home. This cycle would continue virtually to this day: a space is cleared of materials, then it is refined to serve a purpose, whether a home, a hall, a farm. Each new space is built with skilled hands to meet the needs of the population.
Over the centuries, Bastion has developed in three dimensions, growing both outward and downward. Many levels have been excavated through the rock, and while the higher layers are somewhat chaotically laied out, later growth was much more organized and planned. Entire sections are dedicated to a purpose, containing homes for members of a clan as well as their profession, as well as common areas for meeting and interactions between members of various clans. This structure fits the tastes of the dwarfs and their tendencies for order, and a dwarf in the middle levels of Bastion will always know where they are.

Life within the City

Bastion can be briefly described as "a very orderly bustle". Wagoner clan dwarfs move through the city, carrying supplies between mines and forges, between farms and galleys, between the papermakers and the libraries. Military troops march across bridges and viaducts through the caverns. Messengers dart through the city, deftly sidestepping families out to visit friends.
The city is a wonder of stonework and masonry, with natural formations refined into beautiful columns and pathways, and vaulted ceilings built up to support large open spaces. Magically-infused gems and luminescent plants fills the space with a warm, soft, light. From what a casual viewer can see, Bastion is peaceful, well-organized, efficient, and pleasant.
The Dwarfs have created an almost entirely functional ecosystem throughout the city. Farms grow food and other crops in neat rows, underneath artificial sunlight. Where animal-based materials are needed (such as for certain weapons or more rarely for food), occasional pens for them dot the city. Aqueducts run through the city, tapping aquifiers and underground rivers to bring drinking water and irrigation where needed.

In The Depths

As the Dwarfs gradually excavated deeper and deeper underground, they inevitably made some discoveries. The most profound of these were signs that they weren't the first to build underground. The most dangerous was that the surface world faces an existential threat of Elemental chaos - has been since the fall of the Titans. This is the deepest secret of the Dwarfs: they stand as a secret line of defense against this threat and turn their most powerful forces towards that duty.

What lays in the Darkness

Full article: [Titanic Deeps].
Deep below the surface of the world lay the last refuge of the few survivors of the fall of the Giants, which unleashed chaotic elemental energy across the world, causing the Shattered Peak to erupt, which created The Great Plateau and buried the Titans' society under the lava flows. 
Far under the surface, where a handful of those giants hid away after the cataclysm, they continued to build and to dig and to try to forge life. Miles and miles and miles of catacombs, enormous halls with steps six feet high, lay winding through the the stone of the world. The dwarfs are not actually sure who or what built these places - the giants' numbers remain extraordinarily small, to the point where nobody actually knows of their existence - but they consider it a major mystery that possesses the full attention of researches within several clans. 
While the titans have not been found within these halls, they are not empty or safe. For one, even reduced to miniscule numbers, the giants still have a strong urge to create, as they did the Dragons and Elves. There is seemingly no end to the different species of creatures roaming the Deeps, many of which are hostile and jealous creatures. 

In addition to those creatures, there are places where the fabric of reality has become weak or even broken down. Where this happens, the primordial Elemental energy that was present at the world's beginning can break into the "real" world. When this occurs, enormously powerful elementals can manifest and begin wreaking havoc upon whatever they find. The dwarfs, seeing these as obvious threats to Bastion - and the rest of the world - have taken it as their duty to fight these incursions, creating the Bastion Elites as a dedicated force to do so. 

The Shield that stands Against

Main Article: [Bastion Elites].
As the name implies, the Bastion Elites are a hand-selected fighting force, dedicated to defending Bastion and the world from the enormous threat created by elemental incursions in the Titanic Deeps. They have developed fighting techniques, magic, even specialized ceramic-plated armor and massive, mechanized, suits of armor to battle the threats posed. 

Selection into the Elites comes after years of service within one of a number of clans. Naturally, soldiers are the primary membership, but armorers, artificers, and magic users of all kinds are pulled into service of the Elites. The nature of an assignment with the Elites is not commonly known throughout Bastion, simply that it is hard and daunting and dangerous, but the deepest nature of the threat they are fighting against is not commonly shared with the bulk of the citizenry. They are still given the deepest honors by their society for their potential sacrifice and important service, even if most will not know exactly how dangerous that service is.