One of the more impressive things story-telling wise in Wonder Woman the movie was the handling of Steve and the Oddfellows. While the Oddfellows had relatively little screentime, there is a lot of story in them, and I can recommend a rewatch of the movie with a focus on them only; especially Bremner's silent portrayal of Charlie in the background is very expressive.

First factor is that all four of them teach Diana an emotional lesson, but also that they themselves are inspired and become better persons from their associations with her (with the Chief/Napi is a possible exception, at least in the film).

Second is that Diana's view of them changes throughout the movie. In the beginning she has very low opinion of them, perhaps best expressed in the "a liar, a murderer, and now a smuggler" line. She sees Charlie as a man without honour, and finds Sameer distasteful (and for very understandable reasons). But her opinion of them changes throughout the movie, and by the end I believe she considers them friends and companions.

Third is that all of them have lost something, just as Diana has.

Fourth is that they complement each other and act as supporting characters both to Diana and to Steve. And here we go into Wizard of Oz territory: we are not on Themyscira anymore.

Sameer had to give up a career in acting to make a living as a con man due to racism, and then became a soldier. In the beginning he is deeply mercenary and demanding money to join the mission. However, he teaches Diana to see beyond what a person does, or fails to do, when Diana asks him about Charlie after the liberation of Veld. Diana has gained a small degree of trust in Sameer, asks him about Charlie, and gets an answer that relates to Sameer himself, and then Diana looks towards Chief and gets a deeper understanding of him as he refuses payment from the women in the village. Ie, Diana learns how to better see, be aware of, and understand the people around her.

In return, Sameer becomes less egoistic and more willing to help other people, as evidenced when he says he has been paid enough when the group is about to leave Veld. (In Oz terms, he is the scarecrow.)

Charlie suffers from PTSD and self-medicates with alcohol, and as I mentioned earlier I think his silent portrayal in the background throughout the movie is really impressive. He functions in the crossing of No Man's Land, despite being terrified, but he breaks down soon after they reach Veld, putting his companions in risk. However, this is important, they do not blame Charlie for this, but treats him with sympathy. The next morning he shows moral courage by volunteering to stay behind since he feel he is unable to contribute to the continuing mission. Thus, he shows Diana that there are several forms of courage.

For courage, there is also a key scene near the end of the movie, after Diana has killed Ludendorff. She sees Steve and the Oddfellows push on with their mission, after she refused to help Steve. Here, they are more courageous than Diana, and Diana realises it too. She is the coward, not Charlie.

In return, Diana gives back Charlie to himself, reminding him that he is more than a failed soldier with the wonderful "but who will sing for us" line. Charlie's healing (or re-integration) then is shown again in the Etta's Mission scene, where he is shown confident, and choosing to drink tea instead of whisky or beer. In Oz terms, he is the lion.

The Chief has lost everything to the white men, and certainly helps in cracking Diana's binary worldview when he says that Steve's people took the land from his people. However, his lesson is one of forgiveness. He can still help white people, and he can still be friends with Steve. To him, everyone is deserving of help, no matter which side they fight on, or if they fight at all.

I have not been able to work out how or if the Chief is changed by his association with Diana. Perhaps a future movie will give a clue, but I can see him going back to the Americas and tell the story of a headstrong goddess who brought hope to the trenches. In Oz terms, I believe he would be the Tin Man, but the analogy is probably the weakest here.

Steve, as Diana's chief mentor to Man's World, in his turn integrates each of these lessons and makes them to Diana as well. Like them, he lost something to the war: he dreams of peace, but have no idea how to imagine it or what it means.

He shows courage when he pushes ahead after she refuses to help him with his mission, after he had followed him wherever she had went, and then he sacrifices himself in order to destroy the plane without killing more people. He shows Diana awareness of humanity when he says that humans can be both brave, kind, cruel, and evil. And perhaps most importantly, he forgives Diana for her failure to help him earlier when he says goodbye to her and gives her his watch. His role as as carrying pieces of all three is even lampshaded earlier in the movie, when he points out that he himself can be described as both a liar, a murderer, and a smuggler.

This brings us to the key moral scene in Diana's coming of age story, when she is confronted with Doctor Poison. Here, Diana is in a battle for her very soul: she knows so much more about herself and about humanity, and blames herself for Steve's death. It is here that she sees Doctor Poison as a human being and chooses to forgive her.