The tallest man-made structure (with a height of about 12000 m) and the largest skycity in Novera (the world setting of Origin Zero), Tridiasca is the administrative centre of Arlia, home to roughly 3.5 million inhabitants.

It is the epitome of science, engineering and architecture, bringing sky technology to new heights. Almost everything depends on or contributes to the city's ability to stay afloat in mid-air, creating an environment distinct from ground cities. Such elements as aerium city plates and Cloud Towers are unique features of this metropolis, playing essential roles in the city's functionality.

The city plates make extensive use of aerium, a substance with special magiphysical properties: the most important property here is resonative levitation. A powerful core lies within the centre of each of the seven tall Cloud Towers, also made of aerium but with such purity that it resonates with aerium in the city plates, forcing them to horizontally align themselves with the core. In order to affect only aerium cores of the city and not those of other sky vessels, only aerium of a certain natural frequency are used in city construction.

Another special property of Aerium is its aurioactivity, which has a radiating effect on both physical and metaphysical states. For example, the environment is breathable and almost mimics conditions at ground level, even though the atmosphere here is otherwise uninhabitable (although wind is usually unaffected). In addition, the population has been found to have unusual levels of conscious awareness – almost like a “sixth sense”.

With the abundance of wind and sun, Tridiasca is powered mainly by solar and wind power, generating 40% of its own electricity needs with the rest provided by ground-based sources. Wind turbines and roof-top solar panels are a common sight around the city.

A single vertical viaduct runs from the base of Cloud Tower 7 all the way down to the ground, combining elements of science and magic to form one unbreakable umbilical link. This viaduct provides all the necessities unable to be provided by Tridiasca alone, such as water, gas, rapid ground-to-air transport and electricity.

A vast transport network also serves the city. Combined with the layout of the city, rapid and extensive inter-city public transport, and well-organised aero-urban traffic systems, congestion is almost unheard of.

4000 m below the upper city plates, which have commercial and residential purposes, is a city plate almost exclusively assigned to high-tech industries and aeronautical manufacturers. Halfway between these two plate sectors is the Tridiasca International Skyport (shown here as the 6-arm plate), which is a major transport hub serving local and global routes.

The city's purpose is to act as an international trade centre; to provide a unique airborne environment for the high-tech and the aeronautical industries; to serve nearby aerium mining operations; and to provide a unique lifestyle for residents and workers alike. There is also speculation that it serves as an airborne fortress against some malicious threat, but no evidence for this has arisen.