Mami has long red hair, and wears a yellow ribbon and an eye patch which she uses to hide a gaping hole where her eye should be. This contrasts with her older twin sister who has a dark-colored ribbon on her head. She wears a long dark hoodie and apparently no pants; revealing her bare legs.
She is more vicious than her sister, taking down several Anti-Skill before coming face to face with her. In spite of this, she has warned her get out of her way first before she fought her.
Mami and her sister moved into Academy City after their mother was chosen in a lottery. She ran a small a restaurant in School District 4, where the sisters helped her out. They later both went into the Power Curriculum Program, both of them manifesting the Volcanic Ball esper power at the exact same time. However, Mami later gets afflicted by a disease.
Unlike her sister, Mami has had a "abnormal" upbringing somehow allowing her to train her powers to be more of an offensive and power version of her sister's and allowing her to keep using it more than a few times. It is implied that this abnormal upbringing led to her losing her left eye, necessitating in her wearing an eyepatch.
Despite this, she became friends with Himegi Matsuri, letting her escape, wanting her to promise to her to leave the city. However, this is at the cost of her becoming "altered" and made a full member of Full Course.
Toaru Kagaku no Accelerator
- Main article: Nectar Arc
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Tobio is seen encountering her twin sister. Her twin criticizes her for her bad dictions. Yumi calls her by her given name. Mami says that she doesn't go by that name any more. The sisters argue. They fight Yumi realizes they are even and bets it all on a single attack. Tobio surprise her twin with a old attack.
Mami's ability is called Volcanic Ball (