Nishiyama Satomi (nicknamed "Limit") is the daughter of Professor Nishiyama. One year she was mortally wounded during a plane crash. Her father was able to revive her, by making her a cyborg. As a cyborg she is gifted with “Miracle Powers” and several different accessories that aid her in solving different problems. Her red beret can be used as a radio to contact her father, and her boots have super speed. She is also able to transform with her pendant. Limit-chan also has a robot pet dog named Guu. Limit keeps her cybernetic powers a secret, as she fears being shunned by society. She keeps to herself, and sometimes keeps distance from others. Her secret is only known by her father and his assistants. In the final episode she reveals her secret to her teachers.

• Masako Nozawa
• Hidekatsu Shibata
• Sachiko Chijimatsu
• Yoko Kuri
• Keiko Yamamoto