Sachiko Burai

She's a strong fighter, who was put in the cell because of collecting too much badges. She was a friend and a protector of Kumi's sister Towa, before she was killed. She saves Kumi from an attack and escapes from the cell the same day Kumi has transferred to Amazon Academy. After a short while she and Kumi will become friends, when Kumi tells she trusts her. She protects Kumi from the attackers.