The White Cleaver was a servant of Serpine in the first book of the Skulduggery Pleasant series, and later became a hero who worked for the necromancers, he became a villain again when they rebelled but later returns to being a hero, though shortly after he is torn apart by Lord Vile.
Later, Scapegrace offers the Cleavers remains to Doctor Nye in exchange for a new body. Nye revives the Cleaver, but turns him black, so he is called the Black Cleaver from there.
During the war of sanctuarys, the Black Cleaver acts as a bodyguard to Ravel, Misty, Nye and other members of Ravels conspiracy. As such, he also helps them to kill Ghastly Bespoke and Anton Shudder, two close friends of Skullduggery. When he fights him and China in a final attempt to deny them access to Ravel and Misty, Skullduggery uses Lord Vile (or at least Necromancy) to dodge him and to break every bone in his body.
It's not sure if the Black Cleaver is dead, for he is not further mentioned, but it's pretty likely, since Scapegrace stated to Nye, that even torn apart his fingers still moved. Furthermore it appears, that Nye even improved him, so he most likely regenarated after a while. In this case, his further destiny is unknown.