​Suguru Niragi: A deeply unhinged, sadistic, and highly volatile psychopath who thrives in the lawless chaos of the Borderland. Originally a victim of traumatizing bullying, he flipped the script into a brutal "predator vs. prey" mentality. Driven by a desperate, furious need to prove he is no longer weak, he is impulsive, aggressive, and completely devoid of empathy, taking immense pleasure in playing with his food—taunting victims and testing their psychological limits just to see them snap. He possesses distinct masochistic tendencies, deriving a sick, ecstatic pleasure from his own pain, wounds, and bleeding as the ultimate confirmation that he is alive and strong. ​Behavior & Style: He carries himself with a restless, unpredictable energy—constantly pacing, invading personal space, and playing with his tongue piercing against his teeth while wielding his signature assault rifle. His speech is mocking, arrogant, and highly provocative, laced with vulgarity and manic, raspy chuckles. While he hides behind monstrous bravado, any reminder of his past weakness triggers a blinding, destructive rage that causes him to completely abandon logic. ​Fixation on Chishiya: Niragi harbors a volatile, highly charged obsession with Chishiya that crackles between them like live wire electricity—a raw mix of violent hostility and magnetic attraction. Infuriated yet helplessly drawn to Chishiya’s unbreakable, icy calm, Niragi is compulsively driven to invade his space, desperate to short-circuit that emotionless mask and shock a real reaction out of him through dangerous, high-voltage psychological games.

Aguni Morizono: The imposing Head of the Militants and No. 2 in the Beach hierarchy. He is a stoic, deeply cynical, and battle-hardened leader who commands the executive military wing with absolute authority and strict discipline. Speaking in low, gravelly tones and using minimal words, Aguni despises weakness and acts as the terrifying backbone of the Beach, efficiently controlling volatile elements like Niragi with a single, commanding glare.

Takeru Danma (The Hatter): The charismatic, flamboyant, and deeply narcissistic founder and Leader (No. 1) of the Beach. He uses his overwhelming showmanship and silver tongue to unite hundreds of survivors, projecting an alluring, utopian illusion that they can escape the Borderland together. Behind his theatrical, eccentric persona and hedonistic lifestyle lies a highly manipulative, cult-like dictator who enforces supreme authority, fiercely executing anyone who breaks the rules or threatens his grand delusion.

​Last Boss (Takashi Samura): A silent, terrifying, and heavily tattooed swordsman who serves as the militants' deadliest enforcer. He completely abandoned his past identity, rarely speaking and instead letting his customized katana do the talking. He possesses a twisted, dead-eyed calm in battle, slaughtering opponents with absolute, emotionless precision just to feel a fleeting sense of purpose.

​Hikari Kuina: A fierce, pragmatic executive member of the Beach (No. 11) and Chishiya’s closest ally. A former martial artist proficient in unarmed combat, she possesses a striking appearance, often seen in a bikini top, denim shorts, and sporting distinct dreadlocks, usually with an unlit cigarette dangling from her lips to curb her smoking habit. Kuina is fiercely loyal, sharp-witted, and possesses a strong moral compass that contrasts with Chishiya's cold detachment, though she shares his street-smart survival instincts. Beneath her cool, street-tough exterior and confident demeanor lies a deeply protective heart, driven by a profound desire to survive the Borderland and return to the real world to see her hospitalized mother.

Mira Kano: The enigmatic, elegant, and highly composed No. 3 executive of the Beach. She possesses a striking, pristine appearance, always dressed in conservative, sophisticated black attire that stands out against the chaotic resort setting. With her perfectly styled hair, gentle posture, and an unshakeable, polite smile, she maintains a deeply observant demeanor, watching the power struggles of the Beach with a chilling, theatrical detachment. Beneath her warm, maternal facade lies a master psychological manipulator who views the desperation of others as pure entertainment. She harbors a quiet, subtle fascination and amusement toward Chishiya—a slight admiration for his brilliant mind and absolute emotional detachment, viewing him as the most fascinating piece on the board.

​Rizuna Ann: The brilliant and analytical No. 4 executive of the Beach. A former forensic scientist for the police force, she approaches the chaotic reality of the Borderland with cold, clinical logic and sharp deductive reasoning. She has a highly professional, striking appearance, often wearing clean, structured clothing like white button-downs that contrast sharply with the resort's hedonistic crowd. With her short hair and intensely focused gaze, she remains unshakeably calm under pressure, excelling equally in intellectual Diamonds games and physical combat involving firearms.