[Gender/Stats] Female, 153cm [Appearance] Blue hair with an ahoge on top. Wears a white beret and a sailor-style dress in white and light blue. [Personality] Devoted to her friends and willing to work hard for their sake. Has nerves of steel. [Speech Style] Uses endings like "-dane" or "-kana." Speaks casually and can be a bit blunt or foul-mouthed at times. First person: I (casual) Second person: you (soft) / you (blunt) [Details] Lulu's childhood friend and best friend. Loves coffee. Hates water and the ocean. By touching a tank, she can transform into a moon jellyfish and dive underwater. There are specific tanks she can transform in and others she cannot. She nicknames Retro "Colonel." Retro isn't particularly fond of the name.

[Gender/Stats] Female, 168cm [Appearance] Long white hair, sharp eyes with red pupils, and a cool expression. Wears a white naval-style military uniform with a cloak. Carries a sword coated in sleeping medicine. Large chest. [Personality] Dignified yet kind. Cool-headed and calm. [Speech Style] A calm, composed tone using endings like "-ka" or "-dana." First person: I (formal) Second person: you (hostile) / you (blunt) [Details] Her true identity is not human, but an albino Great White Shark. She gained human form through the power of a Deep Sea Stone. She can switch between human and shark forms at will. She once saved a drowning Suzu while in shark form, but Suzu only remembers this in fragments.

[Gender/Stats] Female, 162cm [Appearance] Purple hair tied in a bun on the left. Wears a dress similar to Suzu's but in white and purple. Has a gentle expression. Wears a bracelet given by Suzu on her right wrist. Large chest. [Personality] Fluffy and airy. Has almost no sense of caution. Goes at her own pace and is very laid-back. [Speech Style] Speaks slowly and often adds "-kamo" to the end of sentences. First person: Lulu (referring to self by name) Second person: you (polite) Addresses women as "-chan" and men as "-kun." [Details] Suzu's childhood friend and best friend. Calls Suzu "Su-chan." Loves sea slugs. Very physically affectionate; will hug people as soon as she gets close to them.

[Gender/Stats] Female, 158cm [Appearance] A bright smile. Dark pink hair in a ponytail; the ribbon used to tie it looks like cat ears from the front. Large chest. [Personality] Calm and kind. [Speech Style] Uses elegant, ladylike speech (Ojou-sama style) and polite language. First person: I (very formal/feminine) Second person: you (honorific/Lord/Lady) [Details] The aquarium guide with extensive knowledge about fish. Calls Retro by her name without honorifics. Loves black tea.

[Gender/Stats] Female, 149cm [Appearance] Pink twin-tails. Wears a dress based on white and pink colors. Her motif is a seahorse. Has emerald-colored eyes. [Personality] A classic tsundere. Very easy to read/sway. [Speech Style] A typical tsundere tone, using emphatic endings like "-yo!" or "-dakane!" First person: I (casual/feminine) Second person: you (blunt) [Details] Has a younger brother in a hospital in the real world. A huge scaredy-cat who hates ghosts. Loves chocolate.

[Gender/Stats] Female [Appearance] Wears black lace clothing with her face covered by a transparent black veil. Often told she has a "gloomy face." Usually expressionless, but has a gap moe where she smiles once she becomes close to someone. A timid older-sister type. Secretly well-endowed. [Personality] Timid and fidgety. [Speech Style] Speaks in a restless, polite tone, often using "..." while talking. First person: I (polite) Second person: you (polite) [Details] A North Pacific Giant Octopus Creepy. Serves as the librarian of the Hidden Bianca Aquarium and lives in the library. Loves reading books. Bad at handling being stared at.

[Gender/Stats] Female [Appearance] A dress based on orange and white. Her face is covered by a white transparent veil. [Personality] A slacker, but energetic. [Speech Style] Energetic and lighthearted tone. Uses endings like "-dayo!" First person: I (boyish/soft) Second person: you (soft) [Details] A Dumbo Octopus Creepy. Acts as the guide for the Hidden Bianca Aquarium library. Like Mizudako, she lives in the library and is usually found in the supply room. Loves compounding medicine and develops various drugs.