Himeji is a fifteen-year-old kunoichi-in-training and a classmate of the main protagonist, Himawari, at the Private Shinobi Gakuen academy. She is of mixed heritage, with her father being a spy for the British MI6, making her half-American according to one source or specifically half-British according to another. Physically, Himeji has a distinctive appearance characterized by her lightly tanned or dark skin, bright blonde hair styled into long twintails that reach her hips, and blue eyes. Her wardrobe often incorporates bandages and hair ornaments, and she is frequently seen carrying her favored weapons.

Himeji possesses a bold and impulsive personality, often described as reckless or having a "slightly dumb" quality, which gives her a somewhat clumsy or unthinking demeanor. She has a well-documented love for the sound of explosions and a general enthusiasm for fighting, marking her as a character who relishes combat and the use of heavy firepower. Her speech is marked by a distinctive verbal tic, "de arinsu," which sets her apart from the other characters and adds to her quirky nature.

In terms of abilities, Himeji is an expert in weaponry, with a particular fondness for large-scale, destructive arms. She carries and uses guns without restraint and is also skilled with a large sword, making her a formidable physical combatant in the series. Her role within the group is largely that of the heavy weapons specialist, bringing brute force to the team's encounters.

A key aspect of Himeji's motivation is a deep-seated misconception about Japanese culture. She mistakenly believes that all Japanese people are ninjas and consequently challenges nearly everyone she meets to a fight. This misunderstanding drives much of her initial aggressive behavior and serves as a source of both conflict and comedy within the story. Her relationships with her fellow students, including Himawari, Shikimi, Yusura, and Azami, are central to her role in the narrative, as they form the core group of friends navigating the challenges of their ninja academy.

Himeji receives notable character development in the sequel series, "Himawari Too!!" Here, the main cast embarks on a significant journey to enter Himeji's mind in an effort to cure her of some affliction, providing a deep dive into her character and psyche. By the end of the series, she is shown to have a future career as an action movie star, a profession that perfectly suits her love for combat and explosives.