Since I don't have specific details about this story, I can't name the main characters. But generally, in a story based on true events, the main characters could be the victims, the perpetrators, or those who were witnesses to the events related to the so - called 'killing of the flower moon'.
Without more information, it's impossible to say for sure who the main characters are. However, if we consider the nature of a story about a killing based on a true story, the main characters might include the people directly affected by the event. For example, if it was a crime, the people who were killed or those who committed the crime could be the main characters. There might also be law enforcement or community leaders involved who could be important characters in the story.
As we don't have in - depth knowledge of 'Killing of the Flower Moon Based on True Story', we can only speculate about the main characters. In a story based on true events, the main characters often emerge from the central conflict or event. In this case, if it's about a killing, the victims are likely to be central characters. Their families and friends might also play important roles. And if there was an investigation, the investigators could be key characters as well. There could also be people who had some prior knowledge or connection to the events leading up to the killing, and they would also be part of the cast of main characters.