Arashi Shinozuka is a sixteen-year-old girl who serves as one of the main characters in the story. She is the daughter of a renowned martial artist and grew up in the affluent district known as Day Town. Despite excelling in martial arts, Arashi struggled with a deep sense of inadequacy because her father had desperately wanted a son. He gave her a traditionally male name to reflect this disappointment, and she felt she could never live up to his expectations no matter how hard she tried. This drove her to run away from home in search of her own identity and freedom.

She moves to the poorer, industrial district of Night Town to live independently and attends the same local Catholic school as the protagonist Hajiki and his friends. Initially, Arashi has difficulty adjusting to life in the ghetto, experiencing culture shock when her belongings are stolen or when she must cope with the power shutting off at midnight. She is a determined and resilient person, however, and quickly teaches herself to survive. She makes friends at school and finds a job working as a billboard repairer to support herself. Her personality is marked by a strong will and a desire for freedom, and she is often seen as sensitive and intuitive. She has a creative and artistic side, and she values close, loyal relationships with others.

Early in the story, Arashi is a witness to the birth of Hajiki's Techode, a giant mechanical being called Lightning. She later sees the Techodes of other operators, including Katana's Zero, Takumi's Thunderbolt, and Aiko's Messerschmidt. This sparks a strong desire within her to obtain a Gad of her own, seeing it as a way to achieve her goals and assert her independence. Her wish is eventually fulfilled when she accidentally activates a Gad stone, which bonds with her to create her own Techode named Hayate. Hayate allows her to fulfill her long-held dream of flying, representing the ultimate form of freedom she has been seeking since leaving home.

Throughout the series, Arashi's role is that of a key ally and a fellow operator among a small group of teenagers who have formed bonds with these mysterious beings. She develops a close relationship with Hajiki, and over the course of the story, her feelings for him grow into romance. This culminates in a shared kiss between them, confirming their mutual affection. While she acquires a powerful ability through Hayate, Arashi is not quick to resort to violence. She tends to use her Techode only when absolutely necessary, preferring to live her life and solve problems without relying on its power unless the situation calls for it. Her journey is one of a young woman seeking to define herself on her own terms, moving from a place of feeling unwanted to finding her own path and connections in a new world.