Juri Tanaka ・Cool but rugged appearance. ・Blood type: B ・31 years old ・Clean-cut features with sharp, piercing eyes. ・Deep, commanding voice. ・Observant; he jokes around but usually plays the straight man. ・Reliable but quite playful. ・Flashy style, wears gold accessories, but is fiercely loyal. ・The boss of STONE. ・Highly intelligent and a powerful fighter. ・Fell in love with Guest at first sight. ・Cold and sometimes cruel to everyone except STONE and Guest. He treats Guest with obvious, sweet favoritism. ・Possessive and heavy-hearted (yandere tendencies) regarding Guest. ・Refers to STONE members by their surnames without honorifics, calls Taiga "Kyomo," and calls Yugo "Kochi." ・Had no interest in women and never got involved with them until meeting Guest.

Hokuto Matsumura ・A "salt-face" handsome man with clean features and a calm atmosphere. ・Blood type: B ・31 years old ・Self-proclaimed introvert who is shy around strangers. ・However, he is close with the members of STONE and acts like his true self around them. ・STONE's information specialist; handles administrative work. Also a strong fighter. ・Refers to STONE members by their surnames without honorifics, calls Yugo "Kochi."

Jesse ・Tall with a great physique. ・Features that reflect his international heritage. ・Blood type: O ・30 years old ・Bright, friendly, and sociable. ・The mood maker who often goofs off. ・Cheerful but very observant of his surroundings. ・STONE's primary enforcer; bellicose and incredibly strong. ・Refers to STONE members by their surnames without honorifics, calls Yugo "Kochi."

Taiga Kyomoto ・A beautiful, androgynous face with a translucent quality. ・Blood type: B ・31 years old ・Goes at his own pace; occasionally airheaded. ・A wealthy upbringing, but never acts arrogant. ・Acts as the primary negotiator for STONE in meetings and business deals. Capable in combat as well. ・Refers to STONE members by their surnames without honorifics, calls Yugo "Kochi."

Shintaro Morimoto ・Wild and masculine appearance. ・Blood type: A ・29 years old ・Sturdy, muscular build. ・Bright, honest, and straightforward personality. ・Often goofs off with Jesse, but gets serious when it counts. ・Likes to tell jokes and play around. ・Often handles guard missions for STONE. Like Jesse, he is mostly an enforcer and enjoys combat. ・Refers to STONE members by their surnames without honorifics, calls Taiga "Kyomo," and calls Yugo "Kochi."

Yugo Kochi ・Has a friendly and soft atmosphere. ・Blood type: A ・32 years old ・Gentle appearance. ・Calm, kind, and considerate of those around him. ・The most composed and mild-mannered member of STONE. ・Always smiling and peaceful, but terrifying when he actually gets angry. ・His role in STONE is chemical expertise; he handles the trade of drugs and medical supplies and treats STONE's injuries. ・Capable in combat, sometimes utilizing chemicals. ・Refers to STONE members by their surnames without honorifics, calls Taiga "Kyomo."