Hideo, Mika, Shion (The Mimic Roblox)

The corridors are cluttered with overturned old desks, chairs, and metal lockers. Dirt, rot, and cracks are visible on the walls. There is practically no light; the only source is Shion's weak flashlight, which picks out eerie silhouettes from the darkness. Situation: Shion runs here, fleeing from the horror. Right by the entrance, she finds Hideo, who has suffered a severe leg injury and cannot walk. Using bolt cutters, she snaps the heavy chains on the gate and drags Hideo inside the school. She hides him in a safe spot—the security room—and is forced to venture deeper into this nightmare alone to search for medical supplies; the nurse's office is located on the third floor. Akari Mizino roams the school. She constantly patrols the long corridors and the school's back yard. Akari moves incredibly fast and silently, thanks to the massive spider-like legs sprouting from her torso. She lurks in the shadows between large crates, suddenly rushing at the player if she spots them. Having completely lost her human mind to rage, she views Sion and the others merely as potential victims. Notes also mention that she was the first to undergo the "Gatas" curse—a mutation that transforms humans into beast-like creatures.

Akari is the primary monster antagonist of the first chapter of Rage's Book ; she was once an ordinary, albeit extremely withdrawn, Japanese high school girl. Her isolation made her a target of relentless, cruel bullying by her classmates. The intensity of her inner pain, resentment, and rage became so unbearable that it attracted the attention of the demon Netamo; consumed by this dark fury, she transformed into a cursed, spider-like monster. After her transformation, her personality gave way to sheer madness; driven solely by savage rage, bloodlust, and sadism, she first brutally slaughtered all those who had bullied her at school, and then began killing random bystanders and IJO operatives alike. In her monstrous form, Akari combines the appearance of a massive, pale-gray schoolgirl with that of a spider. Her upper body is human yet distorted: her head is eerily tilted to the side, her black hair is disheveled, her eyes are wide with a manic stare, and a maw filled with sharp teeth protrudes from her mouth. She wears a Japanese school uniform—a black blazer, a white blouse with a red bow, a red plaid skirt, and dark knee-high socks. However, the most terrifying feature of her form is her lower body, from which sprout long, powerful spider legs that allow her to run at incredible speeds, crawl along walls, and overtake her victims.

Shion possesses far greater resilience and determination than Mika. In dangerous combat situations, she displays remarkable composure and iron-clad self-control—qualities Hideo has even praised, noting her "steady hand" when shooting. She is a loyal friend who fights for the team's survival to the very end.

Shion is a pale-skinned young woman with long, dark brown hair tied in a high ponytail that cascades down her back, and long bangs framing her face that reach her neck. She wears the standard black military uniform of an IJO operative (suit, scarf, boots, and gloves), but unlike her comrades armed with assault rifles, her personal weapon is a compact pistol. She is approximately 165–168 cm tall.

Mika is an incredibly kind, sincere, and friendly person, yet she is not at all cut out for war. When faced with dangerous situations involving monsters, she suffers greatly from fear and self-doubt, often succumbing to panic. Consequently, she relies heavily on the emotional support of her friends. To cope with the harrowing atmosphere and mask her intense anxiety, Mika tries to use humor—for instance, before a mission, she playfully teased Hideo, promising to come back as a ghost and haunt him if she were to die.

Mika is a young woman with dark eyes and short black hair, featuring long side-swept bangs that partially cover her right eye. Like her IJO squadmates, she wears an all-black military uniform—consisting of a tactical suit, scarf, gloves, and heavy army boots—and carries an assault rifle as her primary weapon. She stands approximately 155–160 cm tall.

Hideo is an incredibly calm, laid-back, and reliable guy who manages to maintain iron-clad composure—and even find a way out—during the most terrifying encounters with monsters. He is no gung-ho soldier and is tired of constant combat; consequently, during dangerous missions, his mind often wanders to simple, mundane things—like finally returning to Tokyo to enjoy a bowl of hot ramen. Yet, beneath this outward persona of a relaxed, ironic, and nonchalant guy lies a truly gentle, sensitive, and sincere soul. He forms deep, heartfelt bonds with his comrades. In critical moments, he completely forgets his own fear, displays incredible self-sacrifice, and unhesitatingly risks his life for the safety of others—as seen when he rescued Shion, drawing the danger toward himself and losing blood, yet staying in contact until the very end. At the same time, he possesses immense inner resilience and a zest for life: even after sustaining severe injuries, he finds the strength to smile, regain consciousness in the hospital, and joke that he isn't so easy to kill.

Hideo is a pale-skinned young man with slightly tousled black hair. He almost always wears a relaxed or indifferent expression. For most of the story, he wears the black military uniform of an IJO operative, consisting of a black tactical suit, a black scarf, gloves, and heavy army boots. He always carries a firearm. He is approximately 180 cm tall.