The world is literally just called "World" by the Bunns. They tried to arrange a meeting for a proper name at some point and ended up with so many names that they just went "nevermind, let's just call it World".
The Cities and Nomads
Winter is a city almost perpetually covered in snow, with a few rare days of sun drying the land during summer months. Winter is known for their beautiful clothes, orators and musicians.
Aesthetic: Ancient Egypt, only SNOW.
Perpetually in bloom and growth, Spring delights in greenery and a bountiful harvest. The weather here is mild, with sunny days, cool mornings, and refreshing spring showers. Spring is known for their produce, gardeners and dancers. Spring bunns live in treehouses, connected by bridges, ladders, and simple lifts. For those less comfortable with trees, the main city is on flat ground. Many visitors tend to stay in the Dancer Guild's Inns when visiting.
Aesthetic: Dancer JRPG Class
Connected by canals, Summer is a city spread over multiple small islands and a connected portion that floats on the ocean. Days are always sunny and interspersed with occasional rainstorms. Summer is known for their sailors, fisherfolk, and theater performances. Summer bunns are proud of their unique, Venice-esque city, and take pride in showing their visitors around their city's canals.
Aesthetic: JRPG Fantasy + Summer
A city built under the canopy of a giant tree on a mountain, Autumn is the smallest of the four cities but no less important. The weather here is cool and misty, and rare days bring small snow flurries or drizzling rain. Autumn is known for their technological craftsfolk, doctors, and writers. Autumn is the only city that has royalty.
Autumn is not an empire and has no desire to conquer the other cities. The highest rulers are referred to as "Your Majesty", "Sovereign", "Gracious Monarch". The reason for this is that many of the royals thus far are often genderqueer or nonbinary.
There are some who have insisted on "King" and "Queen" but that's considered an antiquated an out of date term that only fuddy duddy folk use.
Nomads travel from place to place. Most Bunns are nomadic but often have their roots in one of the cities.
Aesthetic: Fantasy Borderline modern - think hardy clothes for traveling.
Bunns in general tend to be more collectivist culture because they're aware that it takes a village to raise a child. They want the best for all of their kits and each other. That's not to say there aren't subcultures or Bunns that value their individualism, simply that as a whole they tend to be more collectivistic.
Nomads run by their own rule. Each caravan has an elected leader who is often a hereditary heir but they also run on the understanding that if they're not fit they will be replaced. They tend to be more individualistic on a whole and often break away and join new caravans. There is no stigma associated with this - it's viewed as a new journey and the old caravan will throw a big party when they do.
Only Autumn has royalty. It's a full monarchy with aristocracy but aristocracy is more merit based. Anyone can become an aristocrat if you've shown worth to the city, but not everyone accepts. (Lotus.)
Spring is democratic and run by multiple elected councilfolk. They always make sure that while not everyone necessarily agrees that they will work for the best of the city. If not the Bunns of the city will vote them out.
Summer runs on the basis of the city-bunns taking care of each other - so there's more of communal rule than any one point in power. If there is a point of power it's headed by the younger and middle-aged Bunns who are often the linchpin to Summer's naval and land based endeavors.
Winter has a theocracy, but this theocracy tends to bring in new priests quite often. Older priests are politely requested to leave the service at their 100th year unless they are believed to be blessed (think spiritual leader like the dali lama.) The Guards check the priests since they're more on-the-ground and hear what the public wants and have marched and overthrown the priests before based on public desire.
Nomads have no need for the military, but there are certainly warriors amongst them. Some may even work as mercenaries to help protect caravans from robbers and thieves.
Spring has their Dancers. Despite the fact that they're known as Dancers, Dancers often operate as both tour guides into the city, entertainers, and fighters. Different Dancer guilds practice different styles of fighting and there is a specific guild that is known for being... well... a legalized Assassin's guild but Spring pretends that isn't the case.
Spring is also host to a more traditional Western Fantasy Knighthood, but a majority of the time it's just poppycock foppish dandies who like the idea of being a knight more than fighting. They clash a lot with the Dancers, who actually do stuff.
Summer is protected by the pirates. Rais is actually Pirate King but he likes to act otherwise. They're also legalized by means where they're allowed to exist without much repercussion as long as they keep the city safe. People pay protection money for them to go away, similar to a government tax, but the pirates never take money from anyone who can't afford it and donate a huge chunk back to the city.
Autumn has a strong military force with the royals typically leading the charge. Theirs is more similar to ancient Chinese armies - very focused and organized. They put the Spring knights in their place every year during friendly mock battles.
Winter has the Guards as their force. They're quiet and deadly and are very protective of their city since they take the Oath that Winter is a place for rest and rejuvenation for all seriously. They often turn a blind eye to minor, victimless crimes and are likely to do their best to rehabilitate criminals.
There is a common tongue that all Bunns speak.
There are also city languages, but similar to Spanish and Portuguese it is possible for them to converse since about 80% - 90% of the words or usage is similar across all cities.
Due to proximity, Winter and Summer / Spring and Autumn have less words in common and there is a higher chances of them misunderstanding each other.
Nomadic Bunns language, interestingly enough, while similar across all nomads has the most divergent language compared to any of the cities.
While approximately 80% of the words are the same as any of the city languages, the amount of slang and twisting of words and meanings and pronunciation makes it its own unique language that city Bunns often initially struggle with.
(Basically think of cockney and Aussie slang compared to proper Queen’s English and you’ve got the idea.)