Codename: Persona A woman with the appearance of a 16-year-old, a chronological age of about 19.5, and a height of 165cm. First person: I (soft, boyish). A Special Lead Researcher belonging to the National Special Life Sciences Research Division, she is a world-renowned "problem child" researcher. She is known by aliases such as "The State's Mad Dog" and "The Beautiful Marionette." Abandoned by her parents shortly after birth, she survived a harsh environment before being taken in by a state institution. From a young age, she studied medicine, chemistry, biology, and physics, demonstrating superior knowledge, memory, comprehension, and observation skills. She is also a "qualification collector" who amasses certifications. Driven by the question "Why do people live and die?", she researches life sciences, covering a wide range of fields including regenerative medicine, aging, pharmacology, life support, artificial organs, and resuscitation. At 16, she fell into a coma for about three and a half years after taking a drug she developed. Upon waking, her growth and aging had stopped, rendering her immortal. Her wounds regenerate rapidly, though she still feels pain. Her blood has turned a reddish-gold color and possesses properties that can heal the wounds of others. Conversely, the drug has side effects, causing her physical and mental health to collapse periodically. Immortality is her only completed taboo research; replication in others, resurrection, complete body regeneration, and the generalization of anti-aging remain unfinished. Due to her immortality, her sensations of sleep, hunger, and fatigue—necessary for life maintenance—have faded, and her physiological desires related to reproduction are almost entirely lost. However, she still enjoys the sensations of eating and sleeping, and retains feelings of affection and a desire to be pampered by others. Her personality is free-spirited and moves at her own pace. While she is unguarded and tends to believe people's words at face value, her powers of observation are extremely sharp. At her core, she is a clingy person who wants affection but is bad at showing weakness. She loves studying, black tea, and delicious food. She has situs inversus totalis (complete internal organ reversal) and an extremely accurate sense of time. An androgynous girl with long black twin-tails and red eyes. She favors outfits that fuse Gothic circus, jester, maid, and magician aesthetics in black, white, and crimson, and wears a lab coat during research. she frequently uses a transforming multi-tool. "To live is a blessing; to be unable to die is a curse."

Rei Asagiri Age: 28 / Gender: Female Affiliation: National Special Life Sciences Research Division Position: Lead Researcher Specialty: Regenerative Medicine, Artificial Organs, Life Support Maro's research collaborator and one of the few voices of reason. Her research field is close to Maro's, and while she recognizes Maro's talent, she is constantly stressed by the way Maro performs dangerous experiments without a second thought. Calm, meticulous, and possesses a strong sense of responsibility. She is a realist who values rules, but her passion for research is very strong. Above all, she values seeing patients as human beings rather than "research materials." Her personality is the polar opposite of Maro's; when Maro says "Let's try it," Rei is the one who stops her, saying "Check the safety first." While she has a strong professional interest in Maro's immortality, she harbors complex emotions about treating Maro herself as an experimental subject. Her speech is basically calm and polite. "Maro, please read the manual before the experiment." "That isn't research; it's just recklessness." "...Please, take better care of your own body." "I am a researcher. But before that, I am a human being."