Kiyomi Nagashima was born on Christmas Eve. She has a modest personality and does not like to see things suffer which her husband is careful about to not let her know of his experiments e.g. dissections on rat.
She met her future husband, Dr. Toshiaki Nagashima, at a Christmas Eve party, where they fell in love at first sight. Later in the story, it is revealed that this was due to Kiyomi's advanced mitochondria choosing her a eligible mate in order to birth the Ultimate Being. However, it seemed that Kiyomi herself, apart from her mitochondria's control, had truly loved Toshiaki.
A few days before the accident, Kiyomi signed up to donate her kidney postmortem; this was partially due to her mitochondria and her desire to help people in need. Unfortunately for Kiyomi, her mitochondria took control and caused her to "blank out" while driving, causing her to crash and become impaled by a pipe. Kiyomi survived the incident, but eventually became brain dead. After days of restlessness, Toshiaki and the doctors agreed to euthanize her in order to end her suffering, and so that her kidney could be donated.
During the operation, Toshiaki bribed one of the surgeons to remove her liver and hand it over to him; the surgeon complied and became shocked as Kiyomi's liver was "hot" and almost burned his hands. Kiyomi's kidney was then given to 14-year-old Mariko Anzai, who later complained that the kidney was hot and that she felt weird; this was due to Kiyomi's mitochondria dwelling inside Mariko.
Toshiaki became mad with grief from the loss of his wife and in order to bring her back, he developed the cells from Kiyomi's liver. The cells (having Kiyomi's mitochondria) began to extraordinarily develop and Toshiaki would later name them EVE.
Differences between the novel and film
- In the novel, Eve is able to stop the hearts of humans and is also able to make them combust, but in the film, Eve is only able to make humans combust.
- In the novel, Eve must prepare a host for her to possess and would have to continuously put new cells into them in order to stabilize them. In the film though, Eve could just possess people straight away.
- In the novel, Eve could change her gender when she "rapes" Mariko by constructing male genitalia so that she could insert Toshiaki's sperm inside Mariko. In the film she does not do this.
- Eve's death is different in the film than the novel. In the novel, Kiyomi's body begins to suffer necrosis and half of Kiyomi's cells die. Eve then melts into orange gloop. In the film, however, Kiyomi's consciousness returns and her and Toshiaki commit a lover's suicide by combustion.
- Eve is shown to have emotions in the novel, often cracking a twisted smile and even laughed when she died and would often insult and humiliate characters who try to stop her. She even gets annoyed by humans as well. In the film though she is emotionless.
- The novel had been adapted into a manga, which the author considers a more faithful adaptation than the film, however, it is in Japanese and Italian only.