Tomoko commands a trio of allies in systematically harassing the main characters, employing sexual coercion, physical violence, and psychological blackmail to dominate the siblings. Her relentless pursuit of control is fueled by ignorance of their deeply rooted trauma from familial abuse—specifically, their father’s sexual exploitation and their mother’s emotional abandonment. This shared history of exploitation intensifies the siblings’ fraught interactions with Tomoko, as her aggression inadvertently echoes their past victimization. As an antagonist, she embodies the perpetuation of power-driven cycles rooted in unresolved trauma, though the sources do not delve into her personal motivations, background, or broader narrative trajectory.