Welcome to Caldera, the largest city in the world, as well as one of the oldest. 5000 years ago, Tarisian horse nomads built a small settlement in the crater of an enormous and mostly-extinct volcano. The crater’s 500-foot-high walls stopped enemy raiders in their tracks and so the nomads were able to flourish here, largely left alone, for hundreds of years. They cultivated the land inside during the warm months and built some of the world’s first buildings, and continued to raise their famous Tarisian horses. Over time, a town grew around Mount Aefex, a small flat-topped, cone-shaped peak inside the caldera, where the settlers enjoyed the convenience of the hot springs. They called the city Aefex, too.
Over the next thousand years, Aefex slowly grew. When the Gold Road between the North and South passed near the city, it became an important stop for merchants. When the Sea Bridge crossed the Gold Road nearby, Aefex became a market that dominated all others. At a certain point in the growth of the city, certain mystics and scholars noticed bizarre happenings. The city was coming alive with magic. The world had seen magic before, but it was extremely rare. Miracles of the sort that get written about in history books, but few had claimed to have seen a miracle in person. Aefex changed that. As more people flocked to the city to see the magic with their own eyes, the magic grew in strength and frequency.
In the following millennia, many wars were fought to control Aefex and most failed. Two successes stand out in history. About 2500 years ago, dwarves managed to mine their way under the mountain in secret, a feat that took decades, until they could march an army right into the city. Under dwarven rule, the city prospered and grew in population and physical size. The dwarves built enormous quarries and constructed city in layers, building up and on top of existing buildings while strengthening the lower levels with buttresses and columns. The result is a marvel of architecture, with city blocks on top of other city blocks, and open stair cases and balconies overlooking the lower levels. They also initiated the first public works program, piping water and hot steam around the urban sprawl, and piping sewage out. The dwarves renamed the city Boirnhemme, meaning “good home.”
As other cities began to grow across the world, they also manifested magical effects. By this time, rulers had figured out that the magic was caused by masses of people crowded into small areas (though no one has figured out ’’why’’ this creates magic). To maximize magical potential, monarchs encouraged or forced tens of thousands of people into small areas, designing tall tenement buildings and walled cities to pack citizens in. Still, no city commanded power like Aefex / Boirnhemme, whose population had reached a million people, and whose economic power was unrivaled due to its fortunate location.
About 600 years ago, in a series of the most bloody battles in history, the human King of Rhothes conquered the city and made it the capital of the Rhothesian Empire. He renamed it Caldera and began construction of a defensive wall and towers that will eventually ring the entire 20 mile stretch of the crater walls. His druids learned how to use magic to make the farmlands grow year-round. His engineers mastered steam power, harnessing the geothermic energy to power the city’s mills and presses.
Today, Caldera sits at the heart of the Rhothesian Empire, which has expanded in every direction out from the city-in-the-volcano. The city is the focal point for not only the Empire’s military strength, but also a seat of art, philosophy, arcane research, and engineering. Despite the potential to be the most enlightened place on earth, the crowding of people, combined with the Rhothesian “hands-off” legal system, creates an extremely violent environment within the city walls, where vigilante justice is the norm. The lower castes get pushed to the deeper strata of the city where sunlight cannot reach. Slavery is an accepted fact of life. Government is riddled with bureaucracy and corruption at every level.
Rules for 4E
Character levels are an effect of magical power. Within the vicinity of the city (basically, within the ring of the volcanic crater walls), characters gain levels for their deeds and experience. When a leveled character leaves the city, he temporarily loses one level a day until he reaches 1st level. Once the character returns to the city, he regains one level a day till he reaches his normal level.
Magical devices operate similarly. Their magic is tethered to the city. An enchanted sword will function perfectly in and around the city, but take it away from Caldera and it loses one plus, or one effect, every day. Devices take a month, not a day, to regain each bonus or effect.
Every city with a population of a minimum size can support magical power:
|Population at least||Maximum character level||Maximum magic item level|
Note that this tethers PCs to the city. They can leave, but at a cost of temporary loss of their precious levels. The city is a world of adventure unto itself, however, so players need not despair. Just about any kind of adventure you could have out in the world can be had here in Caldera.