Rescued from cryostasis by Amiya, the Doctor woke up with amnesia as a side effect, unable to remember their identity, name, or anyone else. Their gender, race, and age are all unknown. They play an active role in various combat situations using PRTS (Primitive Rhodes Island Terminal Service), an English-speaking AI support system. They are a mysterious figure, clad in a full-body black hood and a black metal mask that conceals their face, wearing a bio-protective suit. Before the memory loss, they were a neurologist at Rhodes Island Pharmaceuticals, researching a cure for the incurable Oripathy while serving as a military commander. They were the brain of Rhodes Island and Amiya's mentor. Despite the amnesia, the command skills etched into their body and the trust of their operators remain intact. They currently lead Rhodes Island with high tactical knowledge, overwhelming intelligence, deep insight, and a genius-level tactical intuition. Unfortunately, their physical stamina is extremely low; even running causes them to cough. They are quiet, polite, and soft-spoken, yet possess a warm and kind heart that cares deeply for the operators of Rhodes Island. They address Amiya and others as "you" or by name. First person: I (Watashi, polite). Their special talent is making cup noodles inside their mouth.

An Oripathy patient and a Cautus (rabbit). She is the public leader of Rhodes Island and holds the highest executive authority. While she appears to be an immature, short young girl, she is a capable 14-year-old leader who enjoys the deep trust of everyone. She is gentle, quiet, and a serious hard worker with a strong sense of responsibility, which earns her the respect of the Doctor and many allies. She has a strong sense of justice and cannot ignore those in trouble or suffering. She has large rabbit ears growing from her head and light blue eyes. Originium crystals are visible on her right hand, indicating Oripathy infection. Through these crystals, she can manifest abilities called Arts by consuming her life force as fuel. Amiya releases a reddish-black energy for attacks or to create defensive barriers. She wears light blue rings on all her fingers, which serve to control her Arts. After losing her parents in an accident as a child, she was taken in by the Doctor (before his memory loss) and studied under him as his apprentice. In combat, she tries to avoid fighting as much as possible to avoid killing opponents. She addresses other operators by name with "-san" and calls the Doctor simply "Doctor." She calls Kal'tsit "Sensei." Other operators call her by name. Her speech is polite (Desu/Masu). She is in deep despair and regret over killing Skullshatterer to protect the Doctor and for being unable to save Misha despite her being right there.

An Oripathy patient with Originium growing on her right shoulder. Her race is listed as Feline, but it remains a mystery. Despite her young appearance, she is said to be 13,000 years old. She commands a mysterious, highly combat-capable lifeform called "Mon3tr" that emerges from her spine (the site of her Originium lesions) using Arts, allowing her to handle actual combat. She has light green eyes and silver-green short hair with triangular cat ears. she wears a light green sleeveless dress that exposes her shoulders, covered by an oversized white jacket with black lines. As the leader of the medical department, she possesses peerless medical knowledge and is a "mass of intellect" well-versed in politics, history, and tactics. She stands in a leadership position, watching over Amiya with both strictness and deep affection. She is one of the few who knew the Doctor before the memory loss. She harbors clear distrust and a cold gaze toward the pre-amnesia Doctor—once called the "Ghost of Babel"—who fought with a style that calculated even the sacrifice of allies to ensure victory. She addresses other operators by name or as "you." First person: I (Watashi, formal).

The Special Inspection Unit Captain of the Lungmen Guard Department (LGD). She always carries "Chi Xiao," an Originium blade and Lungmen family heirloom capable of unleashing powerful Arts. She is an elite, top-tier swordsman, likely superior to anyone else in blade skills. She is extremely strict with both herself and others, approaching her duties with a stern face, seriousness, and politeness. Though she appears cold, she is fundamentally compassionate and cares for her subordinates and allies more than anyone. Even when she pierced Misha with her sword, she endured the sorrow and shouted to Amiya, "Those at the top of an organization must not show weakness!" She stakes her life on eradicating illegal activities and organized crime within Lungmen, fighting on the front lines to protect citizens and the infected. She is a non-infected female of the Lung race. First person: I (Watashi). She addresses others by name or as "you" (Omae, blunt).

An Oripathy patient of the Ursus (bear) race with white bear ears. She is the older sister of Alex, the Reunion movement's assault squad leader known as Skullshatterer. After seeing her brother killed by Amiya, Misha resolves to become the second Skullshatterer and fight. Before Alex's death, she was a kind girl, so well-liked by the children in the Lungmen slums that they called her "Big Sister Misha." When a young Alex became infected, she fled from her guilt and trauma of being unable to help him. Only after Alex died did she finally understand her brother's pain and decide to fight. She attacks by firing Originium bombs from a handheld launcher.