[SpookyZalost]

The Generic Universal RolePlaying System, or GURPS, is a tabletop role-playing game system designed to allow for play in any game setting. It was created by Steve Jackson Games and first published in 1986 at a time when most such systems were story- or genre-specific.

http://www.sjgames.com/gurps/

closest existing source book would be this one

http://www.sjgames.com/gurps/books/aftertheend/