Hiro Nikaidou

Hiro Nikaidou is a 15-year-old girl and one of the prisoners in Mahou Shoujo no Majo Saiban. An outstanding student from a respected family, she excels both academically and athletically and has held important positions at school. Serious, polite, responsible, and highly self-confident, Hiro appears to be an almost flawless model student.

Hiro possesses an exceptionally strong sense of justice and judges both herself and others according to whether something is "right" or "wrong." She wishes to create a clean world without evildoers and believes that she herself is capable of achieving it. However, her pursuit of righteousness can become extreme, and she shows little mercy toward those she considers "wrong."

Despite her severe attitude, Hiro also has a sensitive side and forms particularly strong attachments to people she genuinely trusts. She has known Emma since before their imprisonment.

Hiro possesses the ability to return to the past after her own death. Upon dying, she can rewind time and retain her memories of events that occurred before the reset.

This allows her to use knowledge gained in previous timelines to change her actions and attempt to produce a different outcome.

Hiro was close friends with Emma and another girl named Yuki. While Hiro was away studying abroad, Yuki was severely bullied. Hiro had trusted Emma to protect her in her absence, but the situation ultimately ended with Yuki taking her own life.

The event deeply affected Hiro. She blamed Emma for failing to protect Yuki and also carried guilt over not being there herself. Her inability to accept what had happened, combined with her obsessive desire to correct what she regarded as an unjust outcome, became closely tied to her extreme fixation on righteousness and her wish to create a world without wrongdoers.

(Source: Mahou Shoujo no Majo Saiban official website and Mahou Shoujo no Majo Saiban Wiki)