Inspired by the Piers Anthony novel "On A Pale Horse", but working on the notion that there are multiple Grim Reapers working the planet.
According to Bryan Fuller, among his problems with the network was that they argued Rebecca Gayheart wasn't pretty enough, to which Fuller replied that she was a supermodel. After the creator left the show, Gayheart's character was written off. She appeared in five episodes only, being replaced by a new character, Daisy Adair, played by Laura Harris.
The version of George that regular people see, played by Laura Boddington, is credited as "Un George".
The red frog that keeps appearing here and there throughout the series comes from the first scene of the pilot. It is, depending on who you ask, the first "person" to die, the first reaper, or both. The frog is an Argentinian horned frog (AKA, the "Pac-Man frog"), which does not make sounds like North American frogs. (During one take, however, the frog hissed when Ellen picked it up, scaring the daylights out of Callum Blue and Jasmine Guy), The "frog sound effect" is dubbed in. The "Pac-Man frog" also has sharp teeth, and should only be handled by professionals, as its bite is very painful.
While Rube's cause of death is never outwardly stated, several of the second season episodes hint that on the night he was killed, Rube tried to rob a bank (the wanted poster Rube finds when searching for information about Rosie, and the gun he's constantly carrying around in his flashbacks).