Achilles is discontent in the underworld, longing for life on earth. He says that Odysseus shouldn't try to "reconcile" him to death: Achilles would gladly go back to earth in the humblest of states rather that stay in Hades:
I’d rather serve as another man’s labourer, as a poor peasant without land, and be alive on Earth, than be lord of all the lifeless dead.
This is ironic, as Achilles was given the choice of being a famous warrior with a short life or an obscure person with a long and fruitful life. He chose fame and an early death, and now says he regrets the decision.
He also asks for news of his son, Neoptolemus. Odysseus is able to fill him in on some details, telling him that Neoptolemus is an eloquent speaker and the best of warriors. Odysseus speaks of his fighting skills and leadership, and says:
he begged me endlessly to let him leap from the Horse, toying with his sword hilt and his heavy bronze spear, eager to wreak havoc on the Trojans.
This feat did not lead to his death: instead, Neoptolemus killed many Trojans and took away his share of war spoils without ever becoming injured. This news makes Achilles very happy, and Odysseus can report that Achilles finally goes away pleased, walking with "great strides" and "rejoicing" in his son's greatness.
Achilles says he would be content to be on earth as a humble laborer, but his speech indicates his heart is still in warfare. He says he wishes he could return to earth for just one hour, so he could use his warrior strength to punish anyone abusing Peleus. He is also very proud of his warrior son.