狭間 エリ

She is a lady who assists the headmaster Nijou as vice principal and head sister at Jingu Gakuen.
She has a motherly personality with a good sense of humor and civility, and is very attentive to her students.
She is loved by many students at the school as "Eri-sensei"

She is deeply concerned about the students and faculty members who are suffering physically and mentally due to the effects of the Dark Hour.
She is a presence who, along with Nijou, sometimes uses her body to provide thorough support for the main character's mission.
She is able to use magic, though not as well as Nijou.