Death

"'I think you look on death as your friend,' she murmured. 'That is a strange friend for a young man to have.'
"The only faithful friend in this world,' he said. 'Death is always sure to be at your side.'"
-Poul Anderson, The Broken Sword (London, 1977), Chapter XXI, p. 153.

Because death defines its opposite, life, Neil Gaiman personifies Death (and see here) not as a hooded man with a scythe but as a perpetually young and beautiful woman. Gaiman also quotes this poem.

Death waits for us all and is always with us as Anderson's character, Skafloc, says. Skafloc and Anderson avoid using a personal pronoun but we need to persuade writers to follow Gaiman's example by calling Death "she." Dream's sister can permeate fiction as she permeates life.