The Doomsday fight

Back again to Batman v Superman: Dawn of Justice: We know that Wonder Woman returned to the field of battle when necessary, and the smile on her face demonstrated she was still a fearless warrior. But why?

In retrospect, she continues on for the same reason she left Themyscira to battle Ares, and that was to save mankind from an exterior threat. The death of her mentor Antiope also motivated her to battle against the God of War. But wasn’t she motivated in a similar fashion in Batman v Superman?

Along with others, Wonder Woman saw a new kind of warrior in Superman. She felt she could look up to him as a protector of mankind (a Steve Trevor 2, if you will). When she saw that the Kryptonian was overwhelmed by Doomsday, she had to intervene and prevent the death of another role model.

This also explains, in part, why she didn't intervene in the Man of Steel events. Earth was under threat, but she wanted to see Earth survive on its own. However, the fact that she was willing to see the world die just to witness the birth of a superhero does put a wrinkle in this explanation.