Kaoruko Usui is a character from the anime Robotics;Notes, where she serves as the Vice Principal of Central Tanegashima High School. She has a distinctive appearance with brown eyes and short gray hair that typically falls to her ears.

Her personality is defined by a strict and severe demeanor that matches her sharp gaze and tone of voice. She holds high expectations for education and generally places the well-being and conduct of students first. However, she can be notably harsh towards those who do not conform to her perception of an ideal student. Kaoruko is an inflexible and by-the-book administrator who demands that students follow school rules and keep their promises, though she is also characterized by a sense of fairness, as she will not break a promise once it has been made.

Within the story, her primary role is as an authority figure who creates conflict for the main characters. She is specifically known to feud with the school's Robotics Club, particularly over its funding, making her an antagonist to the club's activities. Her background includes a connection to JAXA, the Japan Aerospace Exploration Agency.