Does The Grim Reaper work for The Devil or for God?

I remember reading a series in which Death was an office. It functioned as long as there was someone who held the title. The same went for other universal mechanisms. Fate, Time, War, Nature, Good and Evil.
The office holders were humans and would be replaced from time to time to keep everything up to date.
Death can’t be evil or good. It would have to function for both.