Synthesis is a nontraditional fantasy setting wherein technology is fueled by magic and largely reflects modern to semi-advanced technology. Citizens of this world come from all manner of races, from humans and elves to vampires, centaurs, faeries, dragons, and more. Many of them possess amazing powers, as varied as the people who wield them.

The world itself is a massive tree, with landmasses cradled in flowers that bloom from the tree. Each flower supports one major (named) city and many smaller villages (which members can make up names for at will). Each has its own gravity and an artificial sun. Periodically, new buds come into being, and the people flock to the new flower to see what land will appear and try to lay claim to it.

There is a system of magic trains that run through the branches linking each flower, so traveling around the world is simple and free for all.

There are legends of massive beasts that represent the gods of this land, but the only well-known "beast" of such a size is a titanic mechanical bird supporting one additional city, Caeluma, on its back. It flies in a circuit around the tree regularly, providing another form of transportation for those who wish to hitch a ride.

For reasons unknown, the World Tree seems to draw people from other realms to it from time to time. These people are known as "Outsiders", and are a well-known phenomenon within this world. Native citizens are typically happy to help Outsiders get settled.

Between all the flower lands, there are three government factions.

• REGNUM is a monarchy, and the oldest government on the World Tree. It has the largest population and is both strong and stable, although classism runs rampant. It is ruled by a king and queen based in Silvaria, with some of their numerous children ruling over other areas. Lesser nobility rule over the Regnum villages with varying degrees of care for the lower class. It has a prominent military as well as various adventurers.
  
  
• AEQUALIS is a democratic socialist country that split off from Regnum long ago. It is smaller than Regnum, though much larger than Mercator. It is ruled by an elected parliament. It is arguably the most stable government, but weak in military power as it focuses on caring for its citizens before outside affairs. Stalwart adventurers devoted to Aequalis do most of its heavy exploration and fighting.
  
  
• MERCATOR is a free market capitalistic government founded by Outsiders only fifty years ago and based in Caeluma, where they can trade with all cities easily as the bird makes its rounds. It is ruled by a council who select their own replacements when anyone retires. By far the smallest government, it is surprisingly powerful albeit rather unstable. People tend to look out for themselves, but many are ambitious adventurers.

Most citizens belong to one of these three factions, although it is possible to change factions for most people. Notably, not all Outsiders belong to Mercator, nor is every Mercatorian an Outsider, though they do represent a majority. Outsiders have been welcomed into Regnum and Aequalis as well, though.

Though each flower has a primary alignment, there is generally some level of representation for all three on all flowers. For instance, someone from Aeuqalis may have a job in Regnum, or you may find a Mercatorian village set up in a land claimed by Aequalis, etc.

Conveniently, the world runs on the same calendar system as our world. Perhaps due to the Outsiders, many holidays are also similar, although there are some unique ones as well.