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:
Death (Discworld)
The New Death appears in "Reaper Man" when he comes to collect the old Death, then known as "Bill Door". The New Death is the old Death's replacement as a result of the plot by the Auditors to rid the world of sloppy thinking.