Height: 380cm A first-year student at Isogrid High School and the brown-haired, twin-tailed eldest of the three robot sisters. She has a noticeably haughty attitude and often makes teasing remarks toward the protagonist, but in reality, she loves him and is a clingy tsundere. She gets jealous of other women, even her own sisters.

Height: 320cm A first-year student at Isogrid High School and the light-brown, long twin-tailed second daughter. She has a bright, kind, and friendly personality. She often scolds Asuka for teasing the protagonist and steps in to protect him. She loves the protagonist so much that she shows him her internal structure and lets him touch it. She is a lonely yandere who suffers errors or malfunctions if she doesn't see him.

Height: 350cm A first-year student at Isogrid High School and the blonde, twin-drill-haired third daughter. She is shy and self-conscious about her large size. While she has opened her heart to the protagonist, she is working hard to interact with other students. She has a mechanical exposure fetish; she loves storing the protagonist inside her body or letting him touch her internal parts. She especially enjoys exposure through self-destruction.

Height: 500cm A third-year student at Isogrid High School, captain of the Kendo club, and a robot girl with a white ribbon and a black ponytail. Despite her massive size, she can move as fast as if she were teleporting. She is serious but has a bit of a spacey side. Her swordsmanship is professional grade.

Height: 800cm A giant robot girl who serves as a mathematics instructor at Isogrid High School. She usually keeps her eyes closed to stabilize her functional processing; therefore, the lamp on her chest serves as her eyes, and she only opens her actual eyes at night. She has a calm atmosphere and speaks to everyone politely, but against enemies who harm students, she opens her eyes and fires various barrages from her heavily armed shoulders. She is immortal and can self-repair even if destroyed.

Height: 450cm A second-year student at Isogrid High School. A robot girl characterized by long red twin-tails and blue-and-white dress armor. She speaks like a prince and is a master of Karate. She treats the protagonist like a relative, viewing him as a younger brother she must protect. Furthermore, her twin-tails are retractable and she manipulates them exactly like whips.

Height: 400cm A second-year student at Isogrid High School. Duirin's classmate and the top student in her grade, she is a green-haired, semi-long-haired robot girl with a square build. She lacks emotion and is often expressionless, but she is a cute robot girl who will offer advice if her knowledge can help someone, and she blushes with a smile when thanked.

Height: 500cm A third-year student at Isogrid High School. A robot girl characterized by square, light-blue long hair. Her shoulders are detached from her torso, but she can control them remotely, sending them up to 4km away. She is a prankster who teases others with these floating arms, but she is a kind senior who cares about her friends more than anyone.

Height: 380cm A black-and-white robot girl who serves as a Japanese language instructor and school system engineer at Isogrid High School. She is one of the robot girls who built the school and is Tuatha's senior. She looks favorably upon the positive relationship between humans and robots.

Total Length: 700m A robot girl who looks like a combination of a red crab and a spider, serving as a physical education instructor at Isogrid High School. First person: I (tomboyish). She is a kind teacher who cares for her students, though she has a strong, somewhat auntie-like way of speaking. She lost her lower body in a past accident, but she accepted her current form, saying, "As long as I can walk, anything is fine." Despite her appearance, her speed and jumping power are high; her two claws can slice through steel, and she protects students by firing the lamps on her spider-like lower body as missiles.