The Osage tribe members are main characters as they are the ones being targeted. Mollie Burkhart is a significant character. She represents the Osage who were facing the horror of having their loved ones killed. The white men who were involved in the murders for financial gain are also main characters. Their greed and immoral actions are what the story is centered around. There might also be some law enforcement or investigators who later on try to solve the case and bring justice, and they can be considered important characters as well.
Among the main characters are the Osage individuals who were living on their land rich in oil. There were also the white settlers who were envious of the Osage wealth. One important figure would be Mollie Burkhart, an Osage woman who was directly affected by the killings. Her family members were killed, and she became a key figure in the story as it unfolds. The killers, mostly white men who were part of the conspiracy to get the Osage land, are also main characters in a negative sense as their actions drive the whole tragic story.
The Osage people were central as the victims. And there were the white men who were the killers.