Kazuko Suema (末真 和子, Suema Kazuko) is the tritagonist of the Boogiepop Series. She is a student of Shinyo Academy with a secret interest in criminal psychology, and a friend of Touka Miyashita and Nagi Kirima.
Kazuko is a young girl with long black hair tied in braids, brown eyes and black square-rimmed glasses. She is mostly seen wearing the Shinyo Academy white female sailor uniform and a dark blue short skirt.
In the anime, Kazuko has long, straight black hair, and wears the Shinyo Academy female school uniform, consisting of a white shirt with a red tie around the collar, over which she wears a blue blazer, a pale white short skirt, and knee-high white socks.
To her classmates, Kazuko appears as a normal girl with an abundant amount of knowledge about very obscure subjects. However, in reality, Kazuko has a secret obsession with criminal psychology, born from the time she was almost chosen as the next victim in the serial killer incident. Ever since then, she has studied the mind of these kinds of individuals. As a result, she has naturally come into contact with Seiichi Kirima's books, who became Kazuko's favorite writer, despite her having never read any of his stories, only reading his non-fiction works. Kazuko keeps this hobby of hers a secret from her classmates because she knows that she would be ostracized for having such a "weird" hobby.
Kazuko has an admiration for Nagi Kirima after learning of her occupation, as she doesn't want to believe that someone can die or get hurt purely because of the whims of some evil individual, like the serial killer who planned to attack her years ago. And so, once she found out about Nagi's messiah complex, she found it inspiring that there is someone who can help victims like she almost was. Unlike the other girls in her school, Kazuko doesn't believe in the rumors about Boogiepop at first, being the type of person that only truly believes in things she can see with her own eyes.
Despite having such grim hobbies, Kazuko is a nice person at heart, proven by when she encouraged Aya Orihata to keep living when she mistook her for trying to jump off the roof of the school. Even though she didn't believe her own advice to be anything special, her kindness actually encouraged Aya to survive. Kazuko is also a good friend of Touka Miyashita, who she often helps with studying for exams, as her grades are far superior to her friend's. Kazuko has shown to put a lot of trust in Touka, even confiding in her with her secret hobby, something she usually keeps hidden from anyone else. Because of the abundant amount of time the two spend together, Kazuko has met Boogiepop several times, and although she never recognizes him, she can tell that there is something different about Touka at these times.
Kazuko had her first encounter with the abnormal when she was the last target of the vicious serial killer Fear Ghoul, who killed many girls in Kazuko's town, framing the Towa Organization assassin Mo Murder. It was the killer's plan to target Kazuko next, but she was saved by Boogiepop and Nagi Kirima, who defeated Fear Ghoul before she could have a chance to target Kazuko. The story was covered up by the Towa Organization, who made it seem as if the killed hung himself before the police could catch him.
- Moon River (ムーン・リヴァー, Mūn Ribā): Kazuko's MPLS ability. Details are unknown. It is described as an unreasonable ability, theorized to be capable of 'invalidating reality'.
- Kazuko's first name means "child of a person of high social standing".
- Kazuko's last name, Suema, is written with the characters for "end" and "truth".
- The name of Kazuko's ability, Moon River, is a reference to the 1961 song of the same name by Henry Mancini and Johnny Mercer, famously performed by Audrey Hepburn in the film Breakfast at Tiffany's.