The main character is clearly the executioner. But there may be other supporting characters like those she works with, perhaps superiors in her execution - related job, or people in the community where she lives.
The main character is the executioner herself. Other characters may include colleagues in the field of execution or law enforcement related to her work. There could also be civilians in the story's setting who interact with her, either out of fear, curiosity, or necessity. Their relationships with the executioner would help shape the overall narrative and her character development.
The executioner is the central figure in the 'the executioner and her way of life novel'. There could be characters such as her victims or those who are sentenced to be executed by her. Also, there might be family members or friends, if she has any, who play important roles in her life and influence her way of thinking and acting.