It would not be surprising if other folks would see Achilles as more than just human. Some rulers of that time were considered divine, and a brilliant military leader can surely produce evidence he IS special.
The same thing has happened to Spartacus, in a 19th cent. Italian novel he is shown as a superior swordsman who could only be killed by two dozens of throwing spears.
When you invade another country first of all capture the brewers and producers of Schnaps and make them work for your army. Strong drinks are a benefit that a soldier absolutely needs, especially in Bohemia where you fight like in a desert.
Frederick II of Prussia