As a setting idea it is just a rough outline, a little bit of detail. It should be just enough to get a feel for what the setting should be like while leaving enough space to fill in whatever else you want.
NPCs and Organizations have beliefs which are taken from the Burning Wheel RPG. Beliefs are a great way of bringing direction to a character and are there to show what the character is trying to accomplish.
Scenes are ideas of what could be done with character/location/organization. They are something that might happen in the game that strikes me as interesting. Use them (or not) as you see fit.
City In The DarknessThe sun sets on a city, but it doesn’t rise. No stars shine of the city, only the lights from the buildings fill the night. TVs and radios broadcast only static and the phones lines and the internet sit dead.
Nuclear Power PlantThe city has its own power plant near the outskirts which produces most of the city’s power. It is a next generation nuclear power plant. Without the power plant the city would be completely without power, which would draw in the Lightless.
Outside The CityOutside the city there is only black stretched of darkness, and monsters. The creatures that are too repulsed by the light from the city live there and they devour those who attempt to leave. It is unknown how many might actually find a way out of the darkness but the horror stories of those who return are enough to frighten even the bravest of people.
The LightlessThe Lightless are pure white, having no pigment, and blind, though they have no trouble detecting their prey. They are repulsed by bright light which will slowly burn their skin. They hunt and eat each other but humans seem to be their favorite food. They come in various shapes, sizes, and intelligences though it is unknown if any are as smart as humans.
ShadowsThe Other You, The you that has no morals and who will do anything to accomplish its desires, your desires.
Shadows & BeliefsShadows have beliefs that are corrupted versions of the character’s beliefs. The shadow might be willing to follow through with the beliefs no matter the cost or they might be flipped trying to accomplish the opposite of the character.
ScenesA Shadow ruthlessly following through with its believe, killing obstacles that the character wouldn’t.
MidnightA mysterious woman who dresses in a black robe. She has some strange power and the demons seem to fear her. She lives in a broken clock tower that didn’t exist in the real town.
BeliefsTrial brings out the best and worse in people, I must push them to reach their limits.
If the Sun rises then I will be alone again, I will mislead anyone who attempts to make it happen.
ScenesMidnight prevents the party from causing Sun to rise unless they give her someone to keep for ever and ever.
Darkness Comes CultThey were only viewed as another random doom’s day cult, claiming that the world will be plunged into darkness. When the darkness finally did fall their ranks grew and they began taking control of the city.
Cult BeliefsThe Darkness is all, those who seek the rising of the sun must be killed.
The Power Plant is all that protects us from the monsters outside the city, it must be protected at all costs.
We will rule the City of the Darkness, we need any support we can get to accomplish it.
ScenesThe Cult begins holding parts of the city hostage using the Power Plant in an attempt to solidify their control over the city.
Shin Megami Tensei (Nocturne, Devil Survivor, and Persona)
The World Ends With You