[ A vampire and an angel stand in front of the job postings, both heads tilted to the side as they read. Jack has already picked up the poster for the cashier position, because he knows that it's important to get work when trying to survive, but he also doesn't really sleep much so it feels like filling his hours will be a good way to distract himself from the end of all universes coming.

Also it sounds a little exciting. ]

It means working all night long, not an actual graveyard. I think. It's one of those colloquialisms that humans like to use.

[ They don't usually make sense to him either, because he deals better in facts and truths and casual terms confuse him. ]

It's because people prefer working during the day, I guess.