Also known as Number 35, she is a young girl described as the only surviving "third generation" Silpelit (a Silpelit born from one infected by another Silpelit, not by someone infected directly by a Diclonius), and the daughter of Kurama at five years old. During an escape attempt by Number Three, who was actually Nana's sister, Kurama was infected by her vectors, thus becoming a carrier of the diclonius virus, leading to his daughter being born a Silpelit. In the anime, she possesses 33 vectors, each with a range of approximately 11 meters (the numbers are much higher in the manga). Mariko was imprisoned as an infant and raised inside a steel container, with human contact limited to a scientist acting as a foster mother through speakers and monitors. Her physical condition is evidenced by her atrophied limbs, requiring her to move around in a wheelchair.
Despite her upbringing, Mariko is relatively well-developed psychologically. She exhibits extreme homicidal and sadistic tendencies, taking pleasure in torturing and dismembering her victims. However, her personality isn't overtly evil; she simply enjoys it like a child playing with toys. To keep Mariko under control, the research institute implanted at least two bombs in her body during infancy; one was used to remove her right arm after she attacked scientists at the institute. Later, Kurama orders the remaining bomb(s) to be detonated as he walks away embracing his daughter, resulting in both Mariko and himself perishing.
