In Chapter 15, Patroclus personifies "envious Death," painting a grim picture of a heartless entity who seeks to steal Achilles from him:
The rosy gleam of his lip, the fevered green of his eyes. There was not a line anywhere on his face, nothing creased or graying; all crisp. He was spring, golden and bright. Envious Death would drink his blood, and grow young again.
Through figurative language, Patroclus insinuates that Death wants to drink from the font of Achilles's youth, beauty, and power. This may be a vague allusion to the mythical Fountain of Youth, discussed in the writings of Greek historian Herodotus. Many adventurers sought out this fountain, convinced that those who drank from its waters would see their youth restored or receive immortality.
"Envious Death" may also be a reference to Hades, the Greek god given dominion over the Underworld. In Greek myth, Hades is often characterized as resentful of his brothers Zeus and Poseidon. The two held dominion over the sky and the sea, respectively, while Hades remained trapped beneath the ground, with only dead souls for company. Consequently, certain retellings of Greek myths characterize Hades as envious of the other gods, jealous of the vitality and power they enjoy while he remains chained to death. Hades himself could be the "envious Death" who seeks to steal Achilles's life.