The chief chemist associated with General Ludendorff who specializes in chemistry and poisons. On her role, Anaya said, "Well, it was a small role in this big ensemble, but it is an important character in the story. I'm going to be a big nightmare" for Wonder Woman and Steve Trevor. Describing her character, Anaya said, "Dr. Maru loves rage and enjoys people's pain. She's creating terrible weapons, and her purpose in life is to kill as many people as possible, and provoke as much pain as possible". She researched World War I and Fritz Haber, the scientist who created mustard gas, to prepare for the role. On the character's facial scars, Anaya stated, "I went to Patty Jenkins and asked, 'What happened to her?' And she said, 'She did it on purpose.' I was like, 'What? Patty, you're going further than I ever imagined.' She said, 'She wants to provoke painful suffering, so she tested her own gas on her own face. She wanted to know how deep this form of her gas would go, so she put it on her own face.' You can see half of her face is completely gone. This is the sadistic side of Dr. Maru". She also stated her character "is quite the opposite to the lead role of this movie, one of the strongest characters ever of DC comics, Wonder Woman. I can tell you that Doctor Poison is someone with a capacity to provoke so much pain." On Dr. Maru's relationship with General Ludendorff, Anaya said, "I think that they have a relationship based on loyalty. Ludendorff is a very tormented General that lacks self-confidence. That's why, in part, he takes these drugs that Dr. Poison gives him. They are from different worlds, but they complement each other".
Born to Hippolyta, Queen of the Amazons, Diana lived a serene and joyful life until the intervention of Steve Trevor upon the island of Themyscira. A tournament was held among the Amazons to determine the representative that would return to Man's World along with Trevor. Diana defeated the other Amazons but was tasked with the final challenge, deflecting a bullet fired from a gun by her mother. After winning the contest Diana was awarded a suit of armor and the Lasso of Truth and left for the United States, though upon her arrival she was arrested and detained in a cell. Falling into despair, Diana was visited by the Gods of Olympus in their animal forms: a peacock, deer, owl, mouse, eagle, dove and tortoise, who granted her the gifts of strength, speed, endurance, empathy and flight.
Coming to America for the first time, Wonder Woman comes upon a wailing army nurse. Inquiring about her state, she finds that the nurse wanted to leave for South America with her fiancé but was unable due to shortage of money. As both of them looked identical and Wonder Woman needed a job and a valid identity to look after Steve (who was admitted in the same army hospital), she gives her the money she had earned earlier to help her go to her fiancé in exchange for her credentials. The nurse reveals her name as Diana Prince, and thus, Wonder Woman's secret identity was created, and she began working as a nurse in the army.