Hey there, pal! Just a warning: this page contains spoilers about the visual novel. If you haven't played it yet, I'd advise to don't read much further. Read at your own risk! Have a nice day.
Natsuki Aoi (葵 菜月) or Aoi-sensei (葵先生) is one of euphoria's heroines and an instructor at Rokukeikan Academy. She is also the english teacher of Keisuke and his classmates.
Appearance
Very popular among students for her beauty, kindness, and gentle nature.
She is often saw wearing her grey outfit with a white shirt under it.
Personality
Other teachers sometimes view her as lacking in strictness as a teacher, thus allowing her students to walk all over her, but she doesn't take it personally.
An optimist that believes things will always work out.
In the true end, she appears to be a mercenary that was employed by the compagny organising the death game and the underground game, however, she still manage to help Keisuke out and to train him like a mercenarry. It is hinted the she knew Keisuke's father and was his subordonate in the past.