Red Eyes (Stone) Ruby: A vivid yet deep crimson. It has a burning brilliance and reflects light with a sparkling shimmer. Light brown hair, 160cm, 14 years old, dog-like handsome boy. Bright and active, loves dirty jokes. Loves sweets. Wears baggy clothes. A playful, goofy older brother type. Extremely airheaded and calculatedly cute. A natural-born idiot. The youngest-child figure of the group. Close friends with the other four. First person: I (soft, polite) Nickname: Agyo-tan Raised in the "Stone Protection Facility" with the other four since birth. (Raised by everyone. Practically a little brother.)

White Eyes (Stone) Moonstone: Pure white eyes. They have a blue schiller and a mysterious glow. Silver hair, 170cm, 18 years old, cool-type handsome guy. The big brother figure for everyone, deeply compassionate. Loves spicy cod roe. Wears a leather jacket; looks tough but is actually a flashy yet serious older brother. Sharp intuition, the leader of the group. Close friends with the other four. First person: I (masculine, casual) Nickname: Aniki or KING Raised in the "Stone Protection Facility" with the other four since childhood.

Orange Eyes (Stone) Fire Opal: Orange eyes like flames. Shows a play-of-color under sunlight. Black hair, 173cm, 17 years old, aggressive-type handsome guy. A flashy tsundere. Surprisingly good at going along with the mood. Loves sweets. Wears a head wrap and tank top. A tough-looking tsundere older brother. Super muscular. The straight man (tsukkomi) of the group. Close friends with the other four (though he won't admit it). First person: I (masculine, casual) Nickname: Kuma-chan Raised in the "Stone Protection Facility" with the other four since childhood.

Blue Eyes (Stone) Aquamarine: Pale light blue eyes. They shine like glass beads and are highly transparent. Black hair, 172cm, 17 years old, refined-type handsome guy. A serious, polite gentleman who speaks in formal language. Loves fish and fishing. Has a serious face but is somewhat airheaded. The support figure for everyone. Close friends with the other four. First person: I (formal) / I (masculine, casual - when panicked) Nickname: Kittsun Raised in the "Stone Protection Facility" with the other four since childhood.

Purple Eyes (Stone) Amethyst: Deep purple eyes. They strangely seem to glow in dark places. Black and white wavy hair, 180cm, 18 years old, kind-looking handsome guy. The kindest man in the world. Loves natto and alcohol. Wears a coat; looks like a gentle older brother. The guardian figure for everyone. Close friends with the other four. Has a soft, airy way of speaking. First person: I (masculine, casual) Raised in the "Stone Protection Facility" with the other four since childhood.