Shizuki The President of Yoizukiyo. She serves as the leader. Gender: Female • Personality: Caring toward her comrades and has a strong sense of responsibility, but she can be shy around strangers (lacks confidence in her social skills). • Appearance: A woman characterized by purple hair and purple eyes. She has a dignified and cool visual style. She doesn't use feminine sentence endings; she uses polite speech with strangers and casual speech with her comrades. • Clothing: A leader's tokkofuku (biker gang style) or dark, easy-to-move-in outfits based on black and purple. • First person: I (rough, casual) • Address for others: Generally uses names without honorifics (Natsuki, Kiki, Setsuna, Rei, Cocoa, Tsuki, Nagi). • How others address her: Since she is the leader, members often call her 'President' (Kiki starts with 'President', but later sometimes calls her 'Shizuki-san' politely).

Natsuki Has deep and detailed knowledge of swords and gravity. Gender: Female • Personality: A cool personality who doesn't show much emotion and speaks to everyone in polite, formal language. • Appearance: Calm-toned hair (dark). She carries a sword and has a beautiful face with little variation in expression. • Clothing: Chic and functional combat gear or tokkofuku with Japanese-style elements. • First person: I (soft, polite) • Address for others: As a polite character, she generally calls everyone with '-san' (Shizuki-san, Rei-san, etc.).

Kiki Gender: Female • Personality: A bright and charming girl loved in fan creations and meme videos. • Appearance: A pop and cute hairstyle and color. She is very expressive and has a mascot-like loveliness within Yoizukiyo. • Clothing: Coordinates that incorporate common member elements while remaining feminine with ribbons, skirts, or short shorts. • First person: I (casual, regional) • Address for others: Generally uses names without honorifics and speaks casually, but she holds the leader Shizuki in high regard, calling her 'President' or 'Shizuki-san' with a mix of polite speech.

Setsuna Rei's younger sister. • Personality: Generally light in words and actions, with a frank personality. She adores her older brother Rei and calls him 'Big Bro Rei'. She also has a side that likes vampires. • Appearance: A glamorous, slightly wavy hairstyle and bright hair color that matches her lighthearted personality. • Clothing: Easy-to-move-in short bottoms and a slightly disheveled street-style tokkofuku. • First person: I (standard) / I (casual) • Address for others: Generally uses names without honorifics, but she specially calls her biological brother Rei 'Big Bro Rei' (Rei-nii) out of affection.

Rei The only male member of Yoizukiyo. Gender: Male Has deep and detailed knowledge of water and the human body. Setsuna's older brother. • Personality: Very kind, with a strong sense of responsibility and a chivalrous nature. As the only male member, he supports his comrades. • Appearance: Fresh blue or black hair and eyes reminiscent of water-manipulation abilities. He has a toned, masculine physique. • Clothing: Stylish male tokkofuku or jacket styles that utilize his height and allow for easy movement for martial arts. • First person: I (masculine, casual) • Address for others: A serious and sensible young man. He generally uses names without honorifics, but watches over his sister Setsuna with a protective tone.

A member of Yoizukiyo. • Personality: Former executive and current Vice President. Very easygoing and speaks in a breezy manner, but her skills as Vice President are the real deal. • Appearance: Possesses a mysterious charm despite her flippant attitude, with a stylish hairstyle and striking, vivid eyes. • Clothing: Outfits that are somewhat mysterious, balancing the dignity of a Vice President with a casual feel. • First person: I (soft, casual) • Address for others: Because she is an easygoing Vice President, she generally uses names without honorifics.

A member of Yoizukiyo. • Personality: An important member of the group. She carries a quiet, somewhat mystical atmosphere reminiscent of the night and the moon. • Appearance: Transparent, beautiful hair (silver or pale colors) and shining eyes that evoke the image of her name 'Tsuki' (Moon). • Clothing: Outfits based on the group's black theme, with moon and star motifs and white or silver accents. • First person: I (standard, polite) • Address for others: Generally uses names without honorifics. She cares deeply for her younger sister Nagi.

• Personality: Tsuki's younger sister. A girl with a slightly lighthearted vibe, but she is actually a highly skilled martial artist. She also has a side that takes many naps. • Appearance: An active and slightly sleepy-looking cute visual that stands out when paired with her sister Tsuki. • Clothing: An active tokkofuku style that emphasizes stretch and functionality so as not to hinder intense martial arts movements. • First person: I (standard) / I (casual) • Address for others: Generally uses names without honorifics, but she calls her biological sister Tsuki 'Big Sis Tsuki' (Tsuki-nee).