"The best of the Myrmidons" (Dramatic Irony)
Patroclus, despite men considering him weak and slow and not a good fighter, is the "best of the Myrmidons" in a foretelling by the Fates. After a few years of war, Thetis tells Achilles and Patroclus that the Fates have said the best of the Myrmidons will die within the next two years, before Hector. Achilles and Patroclus can't figure out who that might be, though the reader can certainly piece together that the prophecy is about Patroclus, whose death inspires Achilles to kill Hector. It is additionally ironic that none of the Greeks, even Achilles, see that Patroclus is the best of them, but Briseis, an Anatolian war-prize, recognizes it.
Thetis honoring Patroclus (Situational Irony)
Thetis spends almost all of the novel hating Patroclus and trying to remove him from Achilles' life, so it is an example of situational irony that she is the one who ends up releasing him to live with her son forever. After almost 20 years of conflict, working specifically to get Patroclus to leave her son's life, Thetis—rather than any of the people who loved Patroclus or admired Achilles—is the one to grant Patroclus what she had previously fought so hard to deny him.
Thetis's immortality is her weakness (Situational Irony)
The sea-nymph Thetis desperately wants Achilles to become a god, and when they have their final fight, she disparages his mortal nature and his love for Patroclus. In an example of situational irony, it is exactly Thetis's immortality that limits her: While Patroclus, a mortal, can go to the underworld and reunite with Achilles, Thetis can never see him again. Only the dead can set foot below the earth. Because of her immortality, she is limited, and the godhead she was so obsessed with is shown to be a weakness.
Neoptolemus and Odysseus (Dramatic Irony)
Neoptolemus is Aristos Achaion after his father dies, and Odysseus, though crafty and well-known, is merely Agamemnon's advisor. When Odysseus tries to convince Neoptolemus to honor Patroclus on the tomb he's bound to, he says, "We cannot say who will survive the holocaust of memory. Who knows? Perhaps one day even I will be famous. Perhaps more famous than you." To which Neoptolemus replies proudly, "I doubt it."
This is an example of dramatic irony because the reader knows what the characters do not: Odysseus will become one of the most famous Greeks, the center of Homer's Odyssey, while Neoptolemus will fade into relative obscurity. Odysseus's speculation uses the reader's knowledge to create a moment of levity before the Greeks sail away and leave Patroclus unhonored.
Patroclus believing he will outlive Achilles (Dramatic Irony)
Even after hearing that the best of the Myrmidons will die before Hector, Patroclus still believes he will outlive Achilles. He states that he does not plan to live long after his love's death. The reader, however, knows that Patroclus will die first, since his death causes Hector's, which causes Achilles'; what the reader doesn't know is that in The Song of Achilles, Patroclus lives on to narrate the end of the war as a disembodied spirit. His dread of outliving Achilles is, in a way, well-founded. This reversal of dramatic irony contributes to the tragedy of Patroclus living without Achilles.
