Caldera: Adventures
So there's this enormous city, right? And it's like, in the crater of a gigantic, ancient, dormant volcano. And the city blocks are stacked atop each other -- I mean, the oldest streets are like black tunnels under seven layers of newer buildings -- because the city planning officials want to get as many people living as close together as possible. Are they sadists or something? Probably, but that's not why they do it. Thousands of years ago, they figured out that lots of people living in close proximity created magic. Welcome to Caldera.
Caldera is a points of light setting. The city is a kind of dangerous wilderness. Stick to the main roads and public areas, and if you don't have many enemies, you'll probably be safe. Still, you'll have to avoid pickpockets and gangs like every other citizen does. Some sections of the city -- especially the dark recesses buried deep under the newer layers of the city -- get forgotten and abandoned and occupied by awful things, and adventure can lead PCs into danger. At night, the city streets are prowled by monsters and wise citizens shut themselves indoors. Brave adventurers often have business to attend in the dark.
What is unique about this setting?
Well, first, Caldera is a setting, not just a city. It's designed to be the only place characters really ever go. They never leave the city. And if they do, they lose their magic over days, as levels are drained from them. When they come home, they get their mojo back. To be a complete setting, it needs everything that any other D&D setting has. All the action of the game takes place in the city.
Caldera's government offers many opportunities for PC involvement. Because of the crazy, multilevel bureaucracy, there are myriad positions that a PC could fill. At the lower levels there are tax collectors, senator aids, police guards, army lieutenants, and building inspectors (for example). Seemingly mundane positions become dangerous in Caldera. At the higher levels of government are senators, executives, governors, and generals. Players are encouraged to get their characters involved in government at every level and make a change within the system. A lot of settings treat the PCs as outsiders by default. Characters in Caldera have roots, and have a stake in the politics, but can still be dwarven wizards, elven rangers, human bards, or whatever.
What do characters do in Caldera?
In general, characters do what they do in any D&D setting: explore dangerous places, kick ass, take names (and loot), and get more powerful. This is Dungeons & Dragons, dude. But the city is a giant situation generator. Every bit of "color" should be construed as potentially dangerous. It's not just a senate, it's a scheming, amoral senate. It's not just a market, it's a market full of pickpockets and con men.
One of the setting's themes is the proximity of people and danger. While D&D's points of light setting typically treats the city as the "home base" where characters are safe and can rest between trips to the dungeon, Caldera is not safe. The points of light in this setting are a friendly noble house, a guarded workshop, a quiet private library, or a fortified apartment. Furthermore, the most dangerous places in the city are still populated. Deep underground in the "crypts" (forgotten and buried city streets riddled with monsters and magical traps), people still live there. They're just trying to survive like everyone else, but their misfortune and poverty has driven them to live in parts of the city that everyone else considers "the dungeon." Imagine a dungeon crawl where you have to determine at every step who is friend and who is foe. Sure, you can just kill everyone, but what kind of hero would that make you?
There is magic in large gatherings of people. You see it in Caldera itself. Massing two million people into about 4,000 acres has awakened an ancient power, and magic affects everything in the city. This is the passive magic of Caldera. The active magic is sometimes more frightening. Watch how the arena's reality warps as a hundred thousand people cheer on a pair of gladiators locked in a deathmatch. Witness the miracle of resurrection as a large crowd mourns a fallen hero, the tears of the people becoming a kind of elixir of life. Caldera's elite rulers fear this kind of magic, because they cannot control it, and it gives the popular mob terrifying power.
Mirrors are gateways to another realm. Not long ago, the sorcerers of Caldera learned to open mirrors and step into the world behind each one. Since then, more practical wizards have harnessed mirror magic to create a network of communication glass, the fantasy equivalent of modern teleconferencing. More importantly, skilled magicians can mirrorwalk, stepping into the plane of reflection. In that strange world, everything is reflected. A character has a different race and class, and an avatar in that universe doesn't have the character's normal powers (everyone has an alter character for the mirror world, and this character starts at 1st level and advances normally in the plane of reflection, but that experience doesn't transfer to their "real world" self).
So what do characters do in Caldera? It's tempting to answer, "Anything they want!" but that doesn't help describe the Caldera fantasy setting. This is a list of some ideas around which a DM could build an entire campaign.
Gauntlet of BeadsThe city needs new leadership. You are all members of one of the smaller Arima (noble) families, and the head of the family wants to put you into the senate. Of course, to be eligible for the senate, a candidate must first complete the Gauntlet of Beads, a course of political, religious, and military service over many years. You, with help from your friends and family, must build political strength, face down dangerous enemies, deal with blackmail and espionage, and do good works in the city. Impress key members of the senate, and you could join their ranks and solidify your family's power in the city.
Crypt Wardens
As the city piles higher and higher on top of itself, the oldest places get covered over. Even in the daytime, no sunlight touches the cobblestones of some streets. These areas are still inhabited, but not always by people. These poorest of the city's inhabitants have no place to bury their dead. The city's magic has begun reanimating corpses and angry spirits haunt the darkest areas. The temple of the Torchbearer assigns teams of aid workers (led by a priest) to help the unfortunate people down there.
Silver Swords
Your Kura-caste family has a mercantile tradition of a hundred generations. As long as you can remember, you have had the exclusive charter to produce weapons for the Calderan Guard. Recently, your iron mines have come under attack, and you can't meet the senate's production orders. You're sure that a rival family must be behind the assaults. The head of your family assigns you to stop the attacks before the senate gives the charter to someone else.
Avenue of Thieves
You are junior members of an organized crime gang, the Avenue of Thieves. You've mostly stuck to a "protection" racket in a few blocks of the city, but your boss wants to branch out. You'll be muscling in on the territory of some rival gangs and they will meet you with violence.
Chains and Pain
Often strong slaves are forced into gladiator schools and forced to fight for the entertainment of Caldera's citizens. Originally from a small village outside Caldera, you were captured and trained as a gladiator. Since you've been in the city, you and your fellow warriors have been... changing... in odd ways, growing in power and skill faster than anyone has ever seen. Make a name for yourself in the arena! There is glory in death and victory! Perhaps you can earn enough money to buy your freedom.