|Nickname:||Mari, Ms.Mari, Ozono Mariko-sensei|
She has a twin sister named Ms. Yuri who is identical to her and some mistake one for the other. In the anime, she was separated from Ms. Yuri when a meteor hit the plane she was on. Ms. Mari was sick and therefore wasn't there. They are reunited later.
She acts as chaperon to Lan Hikari and his friends on many of his adventures. Ms. Mari brings them to many places and usually ends up caught in the thick of the situation.