The Death of the Discworld universe is a tall figure in black.
Oh, and he is a skeleton who speaks in small capital letters. He made a brief appearance when Agents Suicide and Ithalond were following Sakhmet Black, and might or might not have made a surprise guest appearance in a production of a play commemmorating the events of the Glorious Revolution of the Twenty-Fifth of May, reviewed by the Multiverse Monitor.
Due to his nature as an anthropomorphic personification of an eternal concept, Death cannot be neuralyzed — it is impossible for death itself to ever forget anything in the way a living being or a community of beings could. Despite this, Discworld's Death is very good about playing along with the idea of neuralyzation and not telling any canon characters about their unfortunate badfic escapades or the PPC.