Mayune Awayuki is the eldest biological daughter of Natsue Awayuki, the wealthy widow who marries Himeno’s father. She is the same age as Himeno and lives in the same mansion after the remarriage. Mayune holds a pretentious and haughty attitude toward Himeno, whom she looks down on for coming from a poor family. Her personality is marked by spitefulness and jealousy; she frequently plays practical jokes intended to demean and embarrass Himeno, such as tampering with dining room chairs and setting traps around the mansion grounds. These actions stem from deep jealousy rather than genuine malice, as she feels threatened by Himeno’s presence and resents the disruption to her established life. Mayune’s motivations are driven by a desire to maintain her sense of superiority and to protect her position within the family. She has no supernatural abilities and plays no direct role in the magical conflict of the series; her role is that of a domestic antagonist who creates tension within the Awayuki household. Her key relationships are with her mother Natsue, her younger stepsister Mawata, and her new stepsister Himeno. Throughout the story, Mayune does not undergo significant character development, remaining consistently antagonistic toward Himeno. Notable abilities are limited to her cunning and resourcefulness in devising pranks and social manipulation, but she possesses no magical powers or combat skills.