Netamo-no-Hakai (aka the Beast of Rage) is a primary antagonist and demonic siblings(Sama(Book 1 Control), Enzukai(Book 2 Jealousy), Yuma(Book 4). Born into a cursed bloodline of deities, this powerful, nihilistic entity boasts three terrifying forms, wields a personal pocket dimension, and thrives on inducing fear and paranoia in his victims. He has no eyes so he's blind to show blind rage. “My anger is the only thing that brings color to my dull grey life."

Muki is a terrifying, parasitic creature in The Mimic representing the second mutation stage of Gatas. It is a massive, fleshy, beige or white blob covered in multiple faces, mouths, and eight spider-like legs. Internally unstable, the fused consciousnesses constantly fight for dominance, making this fast-moving monster highly hostile and unpredictable. “Muki is presented to be extremely aggressive and hostile towards humans..."

Baigai is an intelligent humanoid creature in The Mimic with pale gray skin, a bloated physique, and boil-like pods. It has glowing white eyes and a disfigured mouth extending along its left cheek. It ambushes players by teleporting through flooded floors.

Akari Mizuno from The Mimic (Roblox) is a major antagonist in Rage’s Book. A tragic schoolgirl driven to vengeance by brutal bullying, she transformed into a monstrous Shiki-class Gata. Her terrifying, razor-toothed form stalks hallways, using stealth, wall-crawling, and lethal ambushes to eliminate anyone in her path.

Hideo is a supporting deuteragonist in Rage's Book from the Roblox horror game The Mimic. A pale-skinned IJO soldier with messy black hair and a black military uniform, he serves as a loyal comrade to Shion and Mika, fighting off corrupted Yokai. During Chapter I, he is badly injured by a Yokai, bravely telling Shion to flee before being abducted.

Mika is a human soldier and operative in the Bureau of Anomalous Countermeasures (IJO). She features dark eyes, short black hair with bangs covering her right eye, and a black military uniform. Though friendly, kind, and humorous, she struggles with fear and lacks self-confidence.