|Family and Relations||Unknown|
Miss Onchi is an attractive and voluptuous young woman with black hair she wears in a ponytail. She wears glasses and her clothing usually consist of a white coat worn over dark clothes.
Miss Onchi was shown to be an average yet frightened person, having gone through a traumatizing event and quitting her job to get away from anymore similar events.
Miss Onchi had worked in Koji's school for a while with a pretty average life. Her home village was then invaded by Count Brocken and his Iron Cross Corps, she along with several other women were captured, stripped naked, and placed inside spheres attached to Grogos G5. Miss Onchi along with the other women were held hostage during the Grogos' fight with Mazinger Z. After Koji managed to get Brocken distracted by attacking his hovering platform and throwing Brocken's head away, he manages to free the hostages starting with Miss Onchi. Afterwards, Miss Onchi transferred to another school to get away from anymore predicaments much to Boss' displeasure.
- Onchi translates to tone-deaf, implying that it is not her real name.
- While it was never mentioned, Miss Onchi likely got her nickname from being unable to tell the difference between notes, which is ironic considering she was a music teacher.