Long ago the gods fought over the afterlife in order to control the souls there.  This fight went on for over eight thousand years, with one Pantheon or another temporarily seizing full control from time to time, though usually the various factions only temporarily held sections of the underworld.
Eventually, though, an elite level demon named Lucifer, a former servant of the Judaic God, negotiated a treaty between the various factions.  They all agreed to accept a portion of the underworld, with 90% of it being split between the various factions proportionally, based on the number of souls they controlled.  The individual humans would choose a faction upon death, and the factions would then choose what to do with the humans that chose them after that.  Each faction also gained full control over its section, with only Lucifer above them to deal with disputes between the factions and the humans who chose no faction.

We are low or petty level demons who hang out in a specific bar near the main gates.  Our jobs usually consist of dealing with humans, alive or dead, either tormenting them or convincing them to sin.  Not forcing or coercing, though, as those rarely grow properly.  Once they get to the underworld they are harvested of their sin and energy.  The sin is used as a food source, which grows only when a human chooses to do something evil, and the energy, which regenerates, is used as a currency. The standard unit of energy is an Ahnk, one day of energy production from an average human soul.

We mostly just hang out.  Some of us get involved in interpersonal drama, though, or the occasional bit of professional or societal drama.

The bar, named "The Pool" is run by a mid level demon named "Bloodletter" that's been around, assigning temp jobs, for over five centuries.  If you want to earn a few Ahnks, he's the one to talk to.