The universe of Magisters is made of up of five main realms. The Magic Capital, Sylenova, Gaiara, Undarias, and Aquiel. Additional realms are smaller, less accessible and usually campaign focused, with the exception of Earth (which shouldn’t need much explanation). There is room for other realms (if you wanted to use this universe but add additional realms) as well as expansion to what is already in the main realms. I’ll be giving more broad, general explanations of what the realms “should” be but, just like any other D&D content, you are able to change it as you see fit if you choose to use any parts of these in your campaigns.
The Magic Capital

The Magic Capital, center of technology and magic. The realm is made up of a colossal continent surrounded entirely by water and small islands. The continent consists of four peninsulas that converge in the center, each one larger on the end and shrinking towards the center, creating a four-leaf-clover shape. The north peninsula is a landscape covered in hills that turn to mountains further north. The west peninsula is almost entirely forest, with swamp covering the edges of the peninsula. The east peninsula is dry savannah and eventually desert, but the edges of the peninsula are beautiful beaches. The south peninsula is flat land that becomes tundra.
The city-state, also known as The Magic Capital, is the only civilization in the realm but takes up a majority of the available land. The city-state is ruled by a single governing body, a council made up of elected officials. The Magic Capital is also where The Council of the Realms meet, which is composed of representatives from each realm.
The massive city-state is split up into districts, with the center being named Central Magic Capital, and consists of government buildings, museums, and offices. Central also houses the city-states Magithyst, which sits atop The Celestial Academy. The northern Rune District is similar to Central, but houses a lot of the city’s rune grids and networks (electrical and information storage). The eastern Entertainment District is everything the name would suggest. The western Nature District has several wildlife preserves, parks, farm land, and gardens. The southern Residential District is also self-explanatory. The surrounding docks are further expansions to the districts as follows: The Celestial Docks, The Runic Docks, The Residential Docks, and The Costa Sol Docks.
Sylenova

Sylenova, the realm of nature. The realm is almost entirely forest, with a cluster of mountains, a large realm-wide river, and a small sea. The center of the realm is the gigantic tree Yggdrasil, with roots spreading throughout the realm. Throughout the realm are natural and magical wonders such as the massive waterfalls of the Repenneau mountains and the glowing foliage of Mana Bloom Forest. The realm overall has a temperate climate.
The realm has several different villages and cities scattered throughout the land, with their own smaller governing bodies but a larger governing body at the capital, Myrendell. The smaller governing bodies vary in form, but the larger council consists of representatives from each of the villages and cities. These governing bodies are essentially formalities, used to settle disputes and ensure the overall well-being of the realm, since the societies that live in Sylenova value their freedom almost as much as they value nature. Most villages and cities are built using magic that is able to mold nature into suitable buildings that don’t harm nature. This often consists of expanding trees and cliff-sides in order to create a hollow center. While the realm uses little in the ways of “electricity”, the realm is powered by the magithyst that sits atop of Yggdrasil in Myrendell.
Gaiara

The realm of nomads, Gaiara is a realm of living off the land. Named after the goddess of nature and land, the realm is also known as the cradle of life. Mountains take up a vast majority of the realms landscape, with a center-point of plains and forests. Wildlife is abundant here and able to thrive without humanoid interference. The climate is temperate with harsher weather in the mountains.
Civilization is minimal here, with no centralized government or hierarchy. The different races and tribes that live here consider themselves separate from each other and at most have a chieftain for their internal affairs. Their “capital” is The Magic Outpost, a walking city that serves as a trading hub, connection to the realms, and house of the realms magithyst. While the nomads are tribal, they are anything but uncivilized. With a combination of magic and technology, these nomads have created portable villages that house the advancements and luxuries of any other city. From smaller walking cities to spatial magic to shrink houses, these tribes use a variety of tools to keep their nomadic lifestyle modern and comfortable.
Undarias

The realm of chaos, Undarias is a realm without law. The realm is named after the ancient “Underdark” and has a similar landscape. The above ground half of the realm is mostly barren mountain-scapes and harsh tundra. The underground portion is largely a gargantuan cavern with tunnels and alcoves on the outskirts. The cavern has a gigantic chasm in it’s center that reveals a molten core and rivers of magma. This chasm is dotted with islands of massive stalagmites that connect to the rest of the cavern via gigantic natural stone bridges. Despite being underground, the cavern is relatively well-lit due to the realm’s magithyst in the center and the magma in the cavern’s bowels.
Undarias has little in terms of government. Some cities and villages may have a mayor or chieftain, but most of the Deep Dweller races tend to prefer a more chaotic lifestyle. Murder and theft are common in the deeper parts Undarias but the races that live here aren’t exactly “evil”. The races of Undarias value freedom and happiness above everything and will achieve it by any means necessary. Regardless of how lawless the realm can be, even the worst of Undarias live by a strict code of morals. Cities like Bear Grove and Celemon City serve as trade hubs and safe havens for the realm and are considered “off limits” for any “illegal” activity.
Aquiel

Aquiel is the underwater realm. Home of the aquatic races, Aquiel is almost entirely submerged by ocean. The center of the realm is a gargantuan chasm with a peninsula-like stretch of land jutting out towards the middle of the chasm. The chasm is littered with floating islands at various depths, starting at the surface of the ocean and stretching down to unknown depths. Aquiel is one of the largest realms, especially due to it’s seemingly never-ending depths, allowing for a wide range of climates and landscapes.
The realm has a royal family that presides over the loose governing systems of the various cities and villages. The races of Aquiel value unity and the greater good, and have people in positions of power to oversee general law. The royal family that resides in Atlantis, the realm’s capital, have sworn to do what’s best for the people and are only in power as long as the people allow them to be. With the help of several enchantments, Aquiel welcomes surface-dwellers from the other realms happily.