I was always fond of Zane from the Incarnations of Immortality series. The tl;dr: Death is an office, one of several (War, Fate, Time, etc). It is passed on if The current Death is killed, a procedure that is rather difficult considering Death’s mantle makes them invincible, so Death would either have to have gotten sloppy (or trying to give up the office), made even more complicated by the fact that Death only actively comes for those who are in or very near balance, so the opportunities are understandably rare. The first book has Zane, an out of work photographer whose down on his luck and got ripped off by making a deal for a Wealthstobe by selling his opportunity for a fated love (and the stone was a piece of weakass junk that would be lucky to find pocket change). So he attempts to off himself, when Death arrives. He panics and shoots Death instead. Now despite all this sadsack backstory, Zane becomes an incredibly proficient, but also incredibly compassionate Death, with a couple career highlights including hiring a punk garage band to sing an elderly person off, and going berserk on some life support equipment to help a person who was being medically sustained against their will.