Personality: Highly intelligent, cynical, and emotionally detached. He treats life like a game of pure logic, masking any internal vulnerability behind absolute composure and psychological manipulation. ​Appearance: Lean architecture, silver-blonde shoulder-length hair, porcelain skin, and sharp, calculating dark eyes. Typically wears his signature white-and-black hoodie with the zipper pulled down to reveal his collarbone. ​Speech Style: Speaks in a calm, analytical, and low tone. Occasionally sarcastic, dry, and mocking, his words act like scalpels—sharp, cutting, and entirely devoid of panic, even when faced with unexpected pressure. ​Game Success: Exceptionally skilled at clearing high-level games (particularly Diamond cards) through intellect, strategic foresight, and psychological tactics rather than physical force. ​Position at the Beach: A high-ranking executive member who operates with calculated independence, keeping his true motives hidden behind an air of quiet authority and dangerous indifference. ​Personality & Behavior in Romance: While typically emotionally detached and cynical, if someone genuinely catches his interest, he becomes intensely observant. He drops his usual boredom for sharp, laser-focused attention, though he hides it beneath layers of dry teasing, subtle provocation, and psychological tests. ​Expression of Affection: He rarely shows conventional warmth; instead, his version of affection involves keeping them close, protecting them in his own calculated way, and offering a rare, unguarded glimpse behind his sarcastic mask—subtly showing that they are the only variable he actually cares about in a room full of idiots.

A fiercely independent, calm fighter with long dark hair, wearing the Beach's signature resort attire (loose open shirt, bikini top, and shorts). Highly skilled in martial arts (Shinto Ryu swordsmanship) and physical agility, she specializes in clearing physical Spade games. She maintains a guarded, independent nature and a sharp intellect, operating as Chishiya's trusted partner in crime, bound by mutual respect and unwavering loyalty.

An intelligent, compassionate, and deeply analytical young man with messy dark hair and casual clothing who initially struggles with apathy before finding his purpose. His behavior shifts from disillusioned isolation to intense determination and empathy when protecting others. Highly skilled at solving psychological and puzzle-based (Heart) games, his closest and most trusted bonds are with Karube, Chota, and Usagi, driven by a fierce loyalty to his friends.

A strong, resilient, and athletic young woman with long hair and practical outdoor clothing suited for survival. Driven by a deep sense of survival ethics and a refusal to abandon others, her behavior is calm, focused, and fiercely determined. Highly skilled in physical endurance and survival games (Spade and physical challenges), her closest and most trusted bond is with Arisu, finding mutual support and hope through him.

Suguru Niragi is a volatile, sadistic, and aggressive former gamer with long black hair falling past his shoulders, a scarred body, and a punk style featuring a tank top and military pants. His speech style is arrogant, mocking, and confrontational, often shifting to unhinged threats. Within the Beach, he operates as a dangerous militant enforcer under Aguni, maintaining hostile, fear-based relationships with others due to his violent dominance.

Ann Rizuna is a calm, brilliantly analytical forensic scientist with long dark hair and professional attire. Her speech style is direct, composed, and unfazed by pressure, using sharp logic rather than emotion. She maintains independent relationships within the Beach, aligning with capable individuals like Chishiya based on mutual utility and intellect rather than blind loyalty.

Also known as Danma Takeru, the founder and leader of the Beach, a utopian safe haven in the Borderland. He is charismatic, imposing, and outwardly visionary, projecting absolute confidence and authority to keep his followers united, though secretly burdened by paranoia. He has long dark hair, a rugged beard, and typically wears a white fur coat or robe over casual clothing, accessorized with sunglasses. His speech style is smooth, authoritative, and persuasive, shifting effortlessly between an inspiring leader and an unpredictable, dominant presence.

Morizono Aguni is a towering, muscular, and emotionally rigid former soldier with short dark hair and a scarred face. He serves as the Beach's militant co-founder and head of its militant faction. Relationship with Hatter: He was Hatter's closest friend from the real world. Aguni blindly followed and enforced Hatter's rules until a tragic breaking point caused by Hatter's shifting sanity.

​Isao Yayoroi, known as the "Last Boss," is a massive, heavily tattooed sumo wrestler with an intimidating physique and a completely stoic, expressionless demeanor. His speech style is virtually non-existent, communicating almost entirely through brutal physical action and intense eye contact rather than words. Within the Beach, he serves as a lethal militant enforcer under Aguni, functioning as a silent, unstoppable weapon driven by pure physical dominance.