Horror

Story planet is just like Earth other than for it getting darker faster and staying dark for longer.
Has an evil deity titled: "The Darkness".

God: Protek
Goddess: Roma
Lower Deity: "The Darkness"; Aevil

The Triads (Deities) got bored, annoyed, and lonely being the only three in existence. They all pitched in to make the planet "Terro". Protek and Roma strongly forbade Aevil from putting bad in the world, they wanted it to be a perfect paradise.
Aevil disobeyed. While Protek and Roma were asleep Aevil went into the room that held the "globe in progress" on a round table. Putting his hands on the globe Aevil gave the world: freedom of choice, lust, envy, greed, anger, gluttony, pride, laziness, sadness, and insanity, among other evil things.
Protek and Roma were extremely angry with Aevil saying it was bad enough the 3 of them had those things, but mortals who had no control over them? They banned Aevil from "The Realm of the Passed" (as it was later called).
Aevil, seeking revenge, went down to Terro to create chaos, igniting insanity in a select few known as the Chaotics. After the third person was taken over by "The Darkness" everyone realized the one thing that should have been obvious from the beginning... beware of the dark (in general).

No real system. Aevil watches certain young adults (easier to take over yet strong enough to use their new abilities) then takes them over, changing how they look and their mental/physical abilities.

Same as Newton's Laws instead the laws of physics were discovered by Ravan Jerula, so they're called: Jerula's Laws.

Stuff found on Earth and antenna devices that can pick up the energies coming from Aevil (unless he's in watch mode: small amount of darkness). These devices are only on schools, hospitals, Senior Homes, etc.

"The Darkness" makes people become murderous psychopaths.

Along with horror it is also a bit of comedy and very much action.