Yuri Nikaidō

Yuri Nikaidō is one of the teachers at Maijima Private High School. It has been implied in the manga that she is connected to Hell. At the story's progression: It is eventually revealed that she is actually Dokuro whom Keima met in the past. Nikaido is a very strict teacher at Maijima High. It is shown at the beginning that she has a great degree of dislike for Keima because he ignores her lessons and instead chooses to play his video games. Like many other teachers, she is easily aggravated by Keima's daily behavior, but unlike other teachers she physically punishes him for it. This is one of the reasons why Nikaido is seen as a sadist, at least in Keima's view. Conversely, Nikaido is shown to be less strict towards Jun Nagase, her high school junior. She can also be described as aloof, supported by the fact that aside from the irritation she usually directs at Keima, she rarely displays other emotions.