Death (Discworld)
Death has appeared in every Discworld novel, with the exception of "The Wee Free Men" and "Snuff", and had a possible cameo at the end of "Johnny and the Dead" (the character was not identified, but spoke in unquoted small caps). The Discworld books with Death as a leading character, starting with "Mort" in 1987, are:
Discworld II: Missing Presumed...!?
After collecting the souls of a thousand deceased ants, Rincewind's next assignment is Death himself, who was killed by an assassin hired by the Patrician. Not wanting the job of being death for all eternity, Rincewind saves Death by pouring some fresh sand into the hourglass of his life.