An innocent, naïve and childish girl, she is often made fun of because her surname is written with the same kanji for "virgin" (処女 shojo). She is an Extar whose transformation is a large curved sword, though she later gains the power to transform into a double-bladed spear through the Valkyrie Effect.

Unknown to herself, her power level is far greater than Mermaid Island's other inhabitants. As such, and with her compatibility with Mirei, she is able to unleash the Valkyrie Effect, the ultimate manifestation of the powers of the A-Virus which can manipulate - or even cancel - the effects in other carriers.

She liked Guru-Neko since childhood. Previously she was a second-year student at Tokyo Sakuragaoka High school.