Tomoka Kayahara

She is a teacher at the local high school. She is greatly feared by students, because of her creepy appearance and the air of depression around her. Conversely, she dislikes her job because of the pressure she inadvertently puts on students, even though she cares about their futures. The show makes visual references to Sadako Yamamura when Miki, Akihiko, and Megumi first meet her. Ramen puts Tomoka in a completely different mood, and she becomes much more cheerful and incredibly cute when she eats it. Such is the beauty of her appearance in this state that drop-out delinquents fall in love at first sight, and diligently return to school just to see her adorable smile every day.

Megumi doesn't know Tomoka's true identity, and believes she is a vengeful ghost. It is also shown that she can climb up walls like a gekko, causing many people to mistake her for a vengeful ghost. Tomoka is poor as shown in the episode when Megumi first encounters her, she was up on a tree picking peaches for dinner. Also, in one episode you see her room which was really empty and the fact that she traded a plushie for ramen. (source : Wikipedia)