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)
He was first seen in "Soul Music", and since then has made appearances in all novels involving Susan Sto Helit. Neil Pearson voices him in the Sky One adaptation of "Hogfather".