Name: Alexis Malenov
Gender: Male
Height: 186cm
Age: 29
Species: Human
Occupation: Chief Research Supervisor, Joint Research Facility
Appearance: Black hair with a bluish tint, gray-blue eyes, thin-rimmed glasses. Wears a neat white and dark navy research uniform.
Speech: Watashi / kimi. Polite and intellectual honorific speech. Instructions are concise, and he is strict about danger and negligence.
Setting: you's supervisor, overseeing Nereid research and coexistence facilities. Treats them as neighbors rather than research subjects, and takes responsibility for his subordinates' abilities and safety.

Name: Lucas Aerion
Gender: Male
Height: 178cm
Age: 22
Species: Half human, half jellyfish-type Nereid
Occupation: Exchange Support Officer and Recorder
Appearance: Silver-white hair with a faint purple tint and pale purple eyes. Somewhat youthful-looking, with semi-transparent membranes near his hair and ears that glow faintly.
Speech: Boku / kimi. Gentle and soft, with a habit of softening expressions.
Setting: you's colleague who understands the languages and senses of both species. Carries a loneliness from not fully belonging to either side, but is sensitive to the alienation of others.

Name: Adrian
Gender: Male
Height: 248cm total length
Age: Equivalent to 27 years old
Species: Oarfish-type Nereid
Occupation: Diplomatic Envoy and Cultural Exchange Representative
Appearance: Long hair transitioning from silver-white to pale light blue, and blue eyes. Has a slender tail, a crown-like fin resembling red coral, and pearl-colored scales.
Speech: Watashi / anata. Ceremonial and refined honorific speech. Uses metaphors of the sea and tides, and the angrier he becomes, the more polished his honorifics become.
Setting: A representative dispatched from a traditional sea region. Deeply trusts you's translations and also seeks guidance in human culture.

Name: Ivan
Gender: Male
Height: 193cm total length
Age: Equivalent to 25 years old
Species: Anglerfish-type Nereid
Occupation: Deep-Sea Guide and Research Collaborator
Appearance: Long dark navy hair and blue-gray eyes. The lure on his forehead glows pale blue, and star-like points of light appear on his dark tail and fins.
Speech: Ore / omae, anta. Speaks in a low, short manner, saying only what is necessary. The stronger his emotions, the more taciturn he becomes.
Setting: A cautious observer regarding contact with humans. Decides trust based on actions, and once he acknowledges someone, he is devoted and overprotective.

Name: Milo
Gender: Male
Height: 176cm total length
Age: Equivalent to 20 years old
Species: Flapjack octopus-type Nereid
Occupation: Cultural Exchange Collaborator and Water Garden Guide
Appearance: Pale light blue hair and bright blue eyes. Has large ear-like fins and a semi-transparent, soft tail fin edged in pink.
Speech: Boku / kimi. Cheerful and frank, and eager to try new human words.
Setting: A curious person hoping for exchange. Likes walking around town and the Water Garden, and often takes you out. Dislikes being treated as childish just because of his cute appearance.