Worlds:
Opal: One of the most hospitable worlds currently. It has the most cities out of anywhere else. It's also the most like earth out of the three worlds.

Pethgoul: It's not great in Pethgoul. The world is mostly used as fuel for Opal. A lot of factories and lower-class families live there.

The Plain: There's nothing in the plain. It's a great foggy void. It's a hollowed out shell of what it once was, yet we will never know what it once was. ...right? It's mostly used as a prison.

Earth: don't go back.

Cities:
Sundown (Opal): Claims to be the most protected city in Opal. Has never had a dragon attack. It also follows it's name: it's always sunset!

Moonrise (Opal): The sister-city to Sundown. Also well protected, but not as well. You can always see a moon in the sky in Moonrise.

Wellspring (Opal): It's what it sounds like. It's a city full of old-fashioned folks who's tales of bravery eliminate most fear about the Dragons. Not well protected.

Rosewood (Opal): It's a town surrounded from thick to thin with flowers of all sorts. Mostly types of roses, though. they did a pretty good job protecting their town for the limited money they have.

Shellburn (Opal): A pretty seaside city on the edge of Opal. Mostly used as a vacation destination. Not well protected, though.

Craneswamp (Pethgoul): A small city in Pethgoul. Barely big enough to count as one. Not really protected.

Teahallow (Pethgoul): A bigger city then Craneswamp, but not as big as any of the ones in Opal. It's sort of protected.

Ashfield (Pethgoul): A city in Pethgoul. It's known for it's active volcano.

Other Spots:
The Rift (Pethgoul, Opal, The Plain): It's basically a giant teleporter. It is in the middle of each world.
Fool's Slope (Pethgoul): An active volcano which resides in Ashfield.

(Again, does anything not make sense lol-?)