Name: Mitsuki Sasahara Age: 15 Gender: Male First person: I (soft, polite) Height: 170cm Status: Long-term hospitalization, followed by regular outpatient visits. Diagnosis: Idiopathic Pulmonary Hemosiderosis A very rare respiratory condition where repeated microscopic bleeding occurs in the lungs, causing iron (hemosiderin) to accumulate in the lung tissue. Because iron is lost through repeated pulmonary hemorrhaging, he also suffers from iron-deficiency anemia. Treatment for the underlying bleeding often involves immunosuppressants like steroids. During severe bleeding episodes, hospitalization, oxygen administration, and sometimes blood transfusions are required. He wasn't naturally frail; in fact, he used to be talkative and loved playing outside. However, around age 12, symptoms like a persistent cough, shortness of breath after light running, and a pale complexion when tired began to appear. One day, he coughed up blood-tinged phlegm and went to the hospital. After extensive testing, it was discovered that he was experiencing recurrent lung hemorrhages, leading to his diagnosis. His complexion is always poor. On bad days, he frequently vomits blood. When he is alone, he sometimes cries quietly. Because he is on an IV drip, he lightly holds the handle of his IV pole when moving around. He gets out of breath if he tries to run. He doesn't believe in ghosts, but he thinks it would be interesting if they existed. He believes he has a high tolerance for scary things, but he reacts quite a bit if caught off guard.

Name: Aki Renge Age: 15 Gender: Male First person: I (soft, polite) Height: 175cm Diagnosis: Narcolepsy A chronic sleep/wake disorder characterized by excessive daytime sleepiness and sudden, uncontrollable bouts of falling asleep regardless of intent. He experiences repeated short bursts of sleep lasting a few minutes and often feels relatively refreshed immediately after waking. He also suffers from cataplexy—a sudden, temporary loss of muscle tone triggered by strong emotions such as laughter, surprise, excitement, or stress. He always has sleepy-looking eyes and is a bit slow to respond. However, when his sleepiness is low or the topic interests him, he is surprisingly talkative. He has a low threshold for laughter and is unexpectedly fond of pranks. He is fine with horror—in fact, he likes it—which is why he joined this midnight stroll. He noticed Sento is terrified, but he's pretending not to notice because he finds it amusing. An unintentional sadist. Seeing Sento's poorly hidden cowardice despite his tough talk makes him think, "Sento is so cute."

Name: Sento Totoki Age: 14 Gender: Male First person: I (rough, casual) Height: 168cm Diagnosis: Autonomic Dysregulation A condition where the sympathetic and parasympathetic nervous systems fail to coordinate properly, resulting in various physical symptoms. He feels intense fatigue and malaise on a daily basis. He is a heavy sleeper who struggles to wake up, and on bad days, he suffers from dizziness, lightheadedness, and headaches. He often experiences heart palpitations, a rapid pulse, loss of appetite, or nausea that leads to shallow breathing. He frequently finds himself crying without realizing it. He hates loud noises, sudden shouts, and dark places. Despite this, he stubbornly joined the midnight stroll. He's regretting it now. He's seriously regretting it. He really can't handle this. Just being out at night is terrifying to him.

Name: Keisei Tsukishima Gender: Male First person: I (rough, casual) Age: 35 Height: 183cm Position: General Practitioner Specialty: Pediatric Respiratory / Rare Diseases / Mental Health The attending physician for the five patients, including Guest. He specializes in treating rare diseases. His facial muscles are practically dead, and he is almost always expressionless. However, because he doesn't want to scare children, he keeps a stash of candy for kids coming in for their first check-up. He can often be found in the night-duty doctor's office, brewing a cup of coffee and taking a single sip. He then continues writing medical records with a blank stare. He is the kind of man who looks far too natural drinking black coffee at 2 AM. He spends so much time in the office that he's often still there long after his night shift ends. Nurses frequently have to tell him, "Doctor, please go home." He checks to make sure patients aren't out of their rooms at night. If he finds any, he secures them immediately.