Hiasa Sekuro served as an assistant prosecutor on prosecutor Zen Seizaki's investigative team at the Tokyo District Public Prosecutors Office. She was the niece of Yoshifumi Sekuro, the influential Vice Minister of Justice in Kasumigaseki. Her work involved high-profile investigations ranging from a pharmaceutical company's falsified clinical research data to politically sensitive mayoral elections in the new district of Shiniki.

Physically, she had short black hair with bangs swept to the left and brown eyes. She consistently wore conservative, professional attire befitting her role. Her demeanor remained cool and reserved, rarely showing outward emotion during investigations.

Her involvement in probing Shiniki's political machinations and the figure Ai Magase made her a pivotal target. Magase kidnapped her. Hiasa Sekuro met a violent end at Magase's hands, suffering dismemberment with an axe and decapitation. This occurred during a sequence where Magase simultaneously eliminated several others connected to the investigation, including law enforcement officers, while Seizaki listened helplessly.