If Nolan’s Odyssey pulled in Achilles, it would be a curveball because Achilles is dead before the poem starts.
The Achilles Scene in the Original Odyssey, in Book 11 – The Nekyia, Odysseus journeys to the Underworld and meets the shade of Achilles. Odysseus tries to comfort him, saying he must rule over the dead.
Achilles shuts that down with this line: "Better, I say, to break sod as a farm hand for some poor country man, on iron rations, than lord it over all the exhausted dead."
Odyssey 11.489 491, Fagles trans
Odysseus is bleeding sacrificial animals so the dead can speak. Achilles’ ghost drinks the blood, talks to Odysseus, and asks about his son Neoptolemus. It’s bleak. The greatest Greek hero says being the poorest alive is better than being king of the dead.
Why it would be the most surprising include in Nolan’s Odyssey: The Odyssey is post-Trojan War. Achilles died at Troy. Including him means Nolan would have to do a full Underworld sequence. That’s just wild, it’s a horror story in the middle of an adventure epic.
What would be the most surprising include in Nolan's Odyssey from the original poem?