God is the omniscient, omnipotent, omnipresent and omnibenevolent being as defined by certain theistic and deistic religions (and other belief systems) who is most often conceived of as the supernatural creator and overseer of the universe.
God does not physically appear in Reaper and is rarely mentioned but holds a lot of personal history with the Demon and especially the Devil himself who claims that God is his ”one true love” and still loves “Him” if he is in fact a “He” (although the Devil did once state that: "God didn't make mankind in His image. Thats just the Bibles way of trying to be nice"), but has conflicting feelings due to the Fall and God apparently stripping away his ability to eat ice cream, thus making it disappear whenever he touches it. And even though the Devil has stated that in the end as always "God wins", he will still try to defy God until the end.