Who is Death from The Last Continent: A Discworld Novel and what is their importance?

A recurrent character in Terry Pratchett's Discworld novels, Death is a tall figure draped in a black robe, sometimes carrying a scythe. His speech is always set in SMALL CAPS. He carries about large hour glasses measuring the last moments of people's lives. He has many times been frustrated when Rincewind the hapless Wizzard, the protagonist in The Last Continent, evades him. Death's butler, Albert, explains the peculiarities of the arid continent of Fourecks on which Rincewind has been marooned. In his library Death and his companion, the cowled skeleton, Death of Rats, read up on the deadly creatures there. Intrigued, Death visits Rincewind several times just to chat, while en route to fetch other freshly-dead people. This, of course, unnerves Rincewind, particularly the night before he is scheduled to be hanged. Rincewind has been so exposed to magic that he is unreadable.