Mineko Fuji

Mineko Fuji is a teacher of Aihara Academy. She is feared by the students due to confiscating their items and giving them sermons whenever they break the school's regulations. The room where these sermons take place is known as "Mineko's Room".

"Mineko's Room" is a reference to "Tetsuko's Room", a popular Talk Show hosted by Tetsuko Kuroyanagi. Mineko's name appears to be a reference to Tetsuko.

Mineko's name might also be a reference to Fujiko Mine from Lupin the Third.

In the manga, she is commonly drawn in a chibi-like style, while in the anime she is drawn in a more realistic style, possibly to better blend with the other characters.

(Source: Citrus Wiki)