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's Domain
The Mapp shows the parasite universe of Death's Domain. The accompanying booklet provides various details of the Domain, both as portrayed in the Discworld books and newly revealed.