Rei Shimizu

Rei Shimizu (志水 礼 Shimizu Rei) is an antagonist and killer featured in Chapter 2 of Danganronpa Gaiden: Killer Killer, a spin off manga connected to the anime Danganronpa 3: The End of Hope's Peak High School.

Symbiotic Hospital

 *  Main article: Danganronpa Gaiden: Killer Killer - Chapter 2 

Rei is introduced as a suspect in the murder of a young woman called Hana Niyama, who appears to have been killed at Ongō Hospital. On investigating the crime, Misaki Asano notices that the wound appears to have been made by a scalpel, and so suspects that the murderer may be a doctor at the hospital. Rei is interviewed as part of Misaki and Takumi Hijirihara's investigation into the hospital staff, but Takumi develops a crush on Rei at first sight and it causes him to collapse.

When Takumi regained consciousness, Rei discovered that he had disappeared from his hospital ward and searched for him. Eventually she found Takumi inside an archive room, where he was reading the victim Hana's surgical history. Rei asked if Hana was an acquaintance of his.

Later, after Mekuru Katsuragi used her skill, "Drowsing Deduction", to identify that the murderer was in an abandoned institution 50 meters away from the hospital, Takumi headed there and found Rei in an operating theater, about to operate on a patient. Takumi confessed his love to her, but also revealed that he knew that Rei was Hana's murderer. Rei fled the building, but Takumi pursued her into the middle of a forest. After confronting her, Rei admitted that she had planted parasites inside Hana's body one year ago during a surgical procedure, which she had recently harvested through the same surgical wound, and was about to do the same to the patient in the operation Takumi had just interrupted. Rei was also growing parasites within her own body.

Rei's parasites left her body and formed into a gigantic parasite several stories tall, which lunged towards Takumi. Before it could harm him, Takumi killed both the giant parasite and Rei with his knife. After leaving the scene, Takumi deleted all documents regarding Rei from the Special Case Criminal Investigation Unit's database.

Description
Rei is a young woman with messy black hair that she wears in a ponytail. She has large dark eyes, with a small beauty mark under her right eye. She wears a white nurse's uniform with a white nurse's cap and a long sleeved black jacket. Underneath her clothes she wears a black tank-top.

Rei appears to be a kind, but clumsy nurse who cares about her patients, however she truly sees her patients as "parasite hotels" for the parasites she is nurturing.

Modus Operandi
Rei was fanatically obsessed with parasites, which she called "my everything" and her beloved. She would insert parasite eggs into patients having surgery at the hospital where she worked, and would later murder the patients to harvest the hatched parasites. Her own body was also heavily infested with parasites. After her crimes were discovered by Takumi, parasites crawled out of her body and formed a gigantic parasite several stories tall.

Trivia

 * Mikan Tsumiki, the Ultimate Nurse, mentions during an Island Mode Date in Danganronpa 2: Goodbye Despair that she also has a passion for parasitology.