Kazumi is high school aged student near the end of her adolescence with an average height and weight as well as a voluptuous body. She has shoulder length brown hair and brown eyes. Most times, Kazumi was either seen in her school uniform or designer's clothes.
Kazumi is generally friendly and polite, speaking with others in a way that invites a sense of warmness. However in her strive to achieve a life of her own, Kazumi comes across as being very stubborn. At times, Kazumi ignores advice given to her by her peers even the ones she respects like Jun to look like a professional. Because of her wishes to become a model, Kazumi often struggles with looking the part including worrying about her height, getting the right reputation and connections, and even flat-out states that she does not even bother to look for colleges. This passion to get into her career might stem from losing her parents as even though Kazumi loved them as shown by going into shock and weeping uncontrollably, Kazumi seemed to have had issues with them as part of a rebellious phase and desperately had been seeking out attention from other people since.
Kazumi had grown rather close with Jun ever since she moved in with her, calling her "Jun-chan" and treating her like an older sister. Other people call Kazumi names like her Jun's pet by Lan Asuka or lover by others. Kazumi respects Jun as a professional model but gets suspicious whenever Jun goes out for long periods of time that she says are work-related. Whenever Jun gets back home exhausted, Kazumi worries about her and even tears up with the notion that Jun will leave her behind. Upon being captured by the Crusaders and finding out Jun's identity as Devilman Lady, Kazumi's admiration for Jun had grown so much after realizing what Jun had to go through and in spite of the situation wanted to help Jun in any way. Kazumi's last encounter with Jun reaffirmed her feelings for Jun as they both confessed how they really care about each other before Kazumi's death. Even in death, Kazumi would strive for Jun to continue onward in spite of everything.
Kazumi had met Jun upon coming to the agency Jun works at, telling her wishes to become a model like her. Jun tells her that it's a lot of hard work and it could even cost the girl her future. Kazumi did not mind and had showed what seemed to be her passion for this path. Later she and her family are attacked by a Devil Beast. Kazumi managed to get away from the onslaught but her parents were killed in front of her eyes. The Devil Beast was later killed by Devilman Lady, Jun later approached Kazumi and allowed the girl to live with her at Jun's apartment.
Throughout her appearances, Kazumi would interact with Jun but would get suspicious about what Jun was doing, especially with appearances from Lan Asuka and being late out at night. Eventually, the leader of the Devil Beast that killed her parents, Satoru appeared and had Crowe take Kazumi hostage. With Kazumi in danger, Jun is forced to reveal herself as Lady. Kazumi however upon realizing Jun's burdens accepts Jun as what she is while affirming her admiration and love for Jun. Kazumi helps Jun fight the Crusaders but is critically injured by Naberius. With her last breath, Kazumi tells Jun to live on and hope for a better future. Back at their apartment, Jun cremates Kazumi's corpse having lost a crucial piece of her humanity.
In Inferno, Jun is bound to a cross composed of the bodies of the fallen victims of Jun's battles who blame theirs and Jun's fates on her. Kazumi is also there but tells Jun to not see her face while being the only person to encourage Jun. With this, Jun merges with the energy and souls of all the fallen beings becoming an empowered Giga Lady. With the final battle over, Jun notices girls that bear a likeness to Kazumi while showing the girl's own hopes.
- Kazumi's appearance and role as a metaphorical sacrificial lamb for the main character is based on Miki Makimura from the original manga.
- The lead character designer even stated that Kazumi is Miki without her headband.