Shinobu Enomoto 榎本忍

Chihiro's elder sister (but her appearance makes her look like his younger sister), and a math teacher at Rikkyoin. While she can typically be found wearing glasses her personality can change when her glasses are not being worn. She is also very clumsy at times, often falling down sets of stairs and seems to really like sake and just relaxing in her underwear when she doesn't need to be dressed. (wikipedia.org)