Tadakuni's younger sister

Tadakuni's younger sister (Tadakuni no imōto) is one of the eyeless sisters and a first-year student at Central High. Her name is mentioned once in the series by Yoshitake's older sister as "Mei".

Appearance
Tadakuni's sister is of a short and slim stature. She wears her light brown hair in twin tails and is usually seen in school uniform. She is depicted with prominent, sharp canines which are seen when she lashes out at the main trio or gets angry.

Personality
Mei tends to get over-excited when anything good befalls her, such as in Episode 8, where she throws her bag far up a tree. On the other hand, she is quick-tempered and is ready to resort to physical violence, especially against her brother and his friends. She also attacked Vice President for hitting her back, though apologized after she realized he saved her from a deadly hornet.

However, despite her strength and brutality, many characters (maybe including her own brother) are worried about her safety. When she gets into a fight with a boy from her own school, four boys from North High follow her secretly to the spot where she was supposed to meet him, so that she would be safe.

Abilities
Immense Strength: Tadakuni's sister possesses a great deal of physical strength, which often leaves the main trio in shock. She incapacitates Tadakuni with a kick to the stomach, overpowers Karasawa in another instance, and overpowers Hidenori and Yoshitake with a single hand each when they both try to attack her. She is also able to shake a crane game machine that the combined might of the main trio could not budge.