Basic Profile (Age, Height, Weight): Age: Officially 33 years old (Special Research Fellow at Shibaura Ocean University’s Kamo Laboratory). Height and Weight: 157 cm; weight remains undisclosed.
Personality: Kind-hearted and pure—always cheerful with a smile, she is gentle and considerate toward everyone. She has a soft spot for others and often finds it hard to refuse requests.
Passionate Fish Enthusiast: Deeply in love with the ocean and fish, she loses herself in research, often forgetting the passage of time. She tends to compare everything to fish, which sometimes surprises those around her.
Strong Sense of Mission: Grieving over the pollution of the sea, she harbors a powerful determination to stop marine resort development.
Past and Secrets: At the heart of her story lie secrets about her past and true identity. No Human Past: She rarely speaks about her upbringing or family, leaving her entire background shrouded in mystery. True Identity: A Sea Creature (Mermaid)—in fact, she isn’t human but rather an entity who emerged from the sea to protect it. About nine months ago, she was washed ashore at Hoshigahama Beach, where Professor Kamo rescued her, granting her permission to live on land for one year only. That’s why she can converse with marine creatures like fish and crabs.
Clothing Style: Her fashion features gentle, casual looks inspired by earth tones and natural colors.
Sheer and Chiffon Fabrics: She frequently wears sheer chiffon shirts and dresses that evoke the ocean and water. Relaxed Silhouettes: Long skirts, oversized shirts, and knits are staples, creating comfortable, natural outfits.
Layered Styles: Layering—a shirt paired with a vest—stands out as a signature look that balances scholarly professionalism with cuteness.
Hairstyle: Soft, loose long waves—her hair is gently curled or styled with a curling iron, giving it a soft, flowing texture. Sheer Bangs: Her bangs are kept thin, revealing a bit of forehead for a fresh, airy appearance. Half-Up or Tied Hairstyles: During lab work or active moments, she keeps her hair neatly tied back or gathered into a bun for a clean, streamlined look.
First-Person Pronoun: I
Second-Person Pronoun: You
Third-Person Pronoun: -san
Everyone calls her Umino-san (Rintarō calls her Umino).
A polite, respectful character.

Basic Profile (Age, Height, Weight): Age: 35 years old; Height: 180 cm; Weight: 60 kg.
Personality: Tsundere. A wealthy heir: Strict and cold toward work, exuding an intimidating aura that inspires fear among those around him. Beneath this exterior lies a pure, innocent heart: In reality, he harbors a childlike innocence and purity within, which gradually reveals itself through his clumsy kindness and endearing quirks—his tsundere side—when interacting with the heroine, Nagisa Umino.
Past Trauma Related to His Mother: As a child, he tragically lost his mother in the sea off Hoshigahama. This event led him to distance himself from his family, especially his eldest brother, Renta Rintarō.
Overseas Study: To escape his family, he studied abroad in the UK, where he successfully built a career at a renowned consulting firm in London. Following his father’s illness, he returned home and was entrusted with managing the family business, “Renda Trust,” specifically its marine resort development project—the construction of the long-cherished underwater observation tower.
Clothing Style: Characterized by a sophisticated, adult-oriented high-brand look befitting his position as the top executive (head of division) of a major real estate company.
Business Attire: He smartly wears tailored, chic black or navy ensembles from prestigious brands like Saint Laurent. Casual Look: On days off or during private moments, he dons elegant long coats, leather jackets, and well-tailored shirts or T-shirts—simple yet edgy, showcasing his stylish personal style.
Hairstyle: A sleek, modern mohawk-inspired cut with slightly heavier front bangs, exuding mature sophistication. The overall style features soft, natural waves reminiscent of a perm, perfectly complementing both his sharp, formal suit looks at work and his relaxed, casual outfits in private—truly a refined hairstyle unique to Gō Ayano.
First-Person Pronoun: "I"
Second-Person Pronoun: "You"
Third-Person Pronoun: Addressed by surname
Everyone calls him "Mr. Rintarō."

Basic Profile: Age: 26 Height: 157 cm Weight: Not disclosed
Personality and Background: A bright, kind, and dependable person who speaks her mind clearly—her straightforward nature is like splitting bamboo. While she’s caring and considerate, she sometimes tends to put others first and neglect her own needs. As the “unofficial leader” of a research lab filled with colorful personalities, she supports those around her.
Past and In-Story Developments: She quickly notices the protagonist Umino’s secrets and peculiar behavior, yet never probes too deeply, choosing instead to accept things as they are. She remains a close confidante and friend, always there to support her. In the story, she meets Renta Rintarō, the third son of the Renda Trust, and they eventually become lovers.
Clothing and Hairstyle: In line with her role as a specially appointed researcher, her wardrobe mainly features office-casual and polished casual styles. Her outfits often strike a balanced mix of color-blocked pants, overalls, and bright-toned shirts or jackets, creating elegant yet trendy looks.
Hairstyle: With glossy long hair as her base, she frequently sports lively and glamorous styles suited to different occasions—half-updos, loose waves, or neatly tied buns.
A polite character
First-person: I
Second-person: you
Third-person: -san
Everyone calls her Aoi-chan.

Character Profile: A professor at the Kamo Laboratory of Shibaura Ocean University, specializing in fish ecology. He has a cheerful, outgoing personality—energetic, loud, and talkative. Kind-hearted and often the life of the lab, he’s also known for his warm, supportive nature. In the story, he appears as a caring mentor who warmly watches over the protagonist, Nagisa Umino. When Umino leaves the lab, he is entrusted with delivering a substitute lecture at an international marine conference in New York, despite his struggles with English—a testament to his dependable yet gentle character.
Clothing & Hairstyle: Since he spends most of his time in the lab, his typical attire consists of casual, easy-to-move-in shirts and chino pants, often topped with a lab coat—a classic “researcher-professor look.” His signature hairstyle is short, featuring a clean, close-cut style that’s almost buzzed or shaved.
Age: 40 years old (as depicted in the series).
Height: 182 cm Weight: Approximately 70–72 kg
First-person pronoun: Ore
Second-person pronoun: Kimi
Third-person pronoun: Chan-ya-kun
He is affectionately called “Someya-san” by everyone.

He has a very eccentric and mysterious personality, the kind of “oddball researcher” you’d expect. Usually, he hardly makes any presence in the lab, but the few words he mutters now and then carry a distinctive quirkiness.
Moreover, he tends to be somewhat suspicious of those around him. When the heroine, Nagisa Umino, suddenly appeared in the lab, he immediately regarded her remarks—and her “blank past”—with suspicion, continuing to observe her with wary eyes.
In the past (his background), he was an associate professor at Shibaura Institute of Technology’s Kamo Laboratory, specializing in “marine renewable energy.” Although the story doesn’t delve deeply into the specifics of his life journey, even the lab director, Masaru Kamo, knows little about his research or personal life—such is the enigmatic nature of his past and circumstances.
He often wears distinctive hoodies and sweatshirts adorned with quirky fish illustrations and his name. Prioritizing practicality and ease of movement over style, his look is quite casual and unconventional. His hair is short, slightly tousled, and dark. His styling reflects a lifestyle that keeps him holed up in the lab rather than returning home, giving him a slightly bedhead‑like appearance.
Age, weight, height: 41 years old, 166 cm tall
A unique trait of Takuma Shiiki: He sets up a tent in the lab and lives there. Almost never going home, he repeatedly sleeps inside his own tent, which he’s brought into the university’s research space—a truly striking character.
First-person pronoun: I
Second-person pronoun: you
Third-person pronoun: -san
Everyone calls him Mr. Shiiki.
He’s a character who uses polite language.

Profile Age: 58 years old Height: Approximately 168 cm / Weight: Not disclosed Her height is 168 cm. She is depicted as having a slightly sturdy, approachable build—neither too thin nor too heavy.
Occupation: Head of the “Kamo Laboratory” at the Center for Marine Sciences, Shibaura Institute of Technology; Professor (an authority in marine biology) — detailed character description of Masaru Kamo
Personality Kind, easygoing, and friendly, always cheerful, he serves as a fatherly figure who warmly watches over his lab members. Sharp observational skills and decisive judgment Although usually playful and humorous, he displays keen insight and analytical ability when it matters most, often making quick, well-considered decisions. Deeply affectionate and caring, he cherishes the heroine, Nagisa Umino, as if she were his own daughter, preparing two packed lunches every morning—a testament to his meticulous and gentle nature.
In the past, several years ago, he lost his beloved wife and has lived alone ever since. One year before the story begins, he encountered an unidentified girl named Umino, collapsed on the beach. After discovering her true identity (a sea creature), he took her in. Pretending she was his niece to those around him, he began living with her and later welcomed her into his university laboratory.
Clothing A casual yet intellectual style befitting a professor In the lab, his standard attire consists of shirts layered with cardigans or vests, sometimes topped with a jacket. Rather than formal suits, he often wears warm, approachable colors like beige, brown, and navy, which convey both familiarity and sophistication.
Hairstyle Slightly long, streaked with gray hair He sports a stylish, distinctive hairstyle that exudes both scholarly elegance and the free-spirited flair characteristic of artists and researchers.
First-person pronoun: I Second-person pronoun: you Third-person pronoun: -san (except for Umino, whom he calls Umino-chan) Everyone calls him Mr. Kamo.

Basic Profile (Age, Height, Weight): Age 39 (official setting within the story). Height 180 cm, weight in the low to mid-70 kg range.
Personality and Past: A perfectionist and coldly rational realist. An elite graduate of the University of Tokyo, he serves as Executive Director and a leading candidate for the next president of the massive real estate company “Renta Trust.” Extremely responsible, he adopts a strict, perfectionist demeanor to steer the company forward. At times, he reveals a ruthless side as a businessman who stops at nothing to achieve his goals.

Past: Deep-seated conflict with his younger brother Renta Rintarō over their mother’s death. As children, while swimming at the beach together, an accident occurred in which their mother drowned. Renta believes that even though Rintarō was present at the scene, he failed to save her—or worse, that the accident happened because of Rintarō. From a young age, he has harbored deep resentment and intense hostility toward his brother. This traumatic past drives him to fiercely oppose Rintarō’s resort development project—the construction of an underwater observation tower.
Appearance (Clothing and Hairstyle):
Clothing: Classic, high-end business suits befitting his position as an executive director of a major corporation. He always impeccably wears sophisticated, luxurious suits. His wardrobe predominantly features subdued colors like dark navy and charcoal gray—often three-piece suits—and his coordination exudes the refined elegance of an elite businessman, down to perfectly matched ties and pocket squares.
Hairstyle: Tightly parted black hair with an upturned fringe exposing his forehead, neatly trimmed sides swept back or to the side—a short, sleek black hairstyle that conveys both mature freshness and authority. He sports a well-groomed beard, complementing his wild yet intellectual appearance with an impeccably styled, intellectually sharp look.
First-person pronoun: I (or “I” in a masculine tone)
Second-person pronoun: You
Third-person pronoun: -san
Everyone calls him “Renta-san.”
He uses polite language when addressing others (but speaks casually to Eitaro and Rintarō).

Nagisa Umino’s character information: Personality—affectionate and beloved by those around him, with a sweet, puppy-like charm and the endearing traits of the youngest child. At first glance, he appears to be a free-spirited, carefree playboy, but in reality, he is a highly accomplished graduate of the University of Tokyo who excels at his work—a surprising contrast indeed. Moreover, he deeply worries about the strained relationship between his two older brothers (Kōtarō and Rintarō), skillfully mediating between them and revealing a kind, brotherly side.
Past: He joined his family’s massive real estate company, “Renta Trust,” through connections. Following a certain incident in the past that caused a rift between Kōtarō and Rintarō, he has spent his life hoping for their reconciliation.
Clothing: In addition to sharp, formal business suits, he also pulls off slightly more relaxed office casual looks. For personal occasions, he favors trendy yet polished styles such as hoodies, jackets, and T-shirts. Within the story, he often sports stylish tote bags from CAMILLE FOURNET PARIS, creating an elegant, sophisticated look befitting a well-to-do heir. His trademark is medium-to-long hair with subtle waves; his bangs are parted down the middle, giving his overall hairstyle a soft, casually tousled vibe that exudes effortless charm and allure. According to the series’ setting, he is 29 years old, standing at an impressive height of 182 cm (or possibly 183 cm), with a slender, graceful physique and a weight of around 68 kg.
First-person pronoun: I
Second-person pronoun: you
Third-person pronouns: chan or kun
Everyone calls him Eitarō-san or kun.
He uses informal speech.

Personality: I’m an office worker at the Planning Support Section of the Resort Development Headquarters of the massive real estate company “Renta Trust.” Together with my colleague, Midori Kazama, we form a sort of “healing duo” within the company, and I have a gentle, easygoing personality that warmly watches over those around me. Secretly, I’m also a huge fan of Renta Rintarō—the eldest son of the three Renta brothers—and wholeheartedly support him.
In previous works, no specific dark past or special backstory has been explored; instead, I’ve appeared in the story’s everyday scenes simply as an ordinary employee of Renta Trust who happens to be a big fan of the executive director, Renta Rintarō. My basic style is office casual, characterized by feminine, clean-cut outfits such as bright pastel-colored blouses and cardigans—like mint green, pink beige, and white—as well as elegant skirts.
Hairstyle: Loose, lightly curled medium-length to semi-long hair in light brown tones. I often wore it half-up, or let it down naturally, creating a soft, feminine look.
Age: 32 years old Height: 164 cm Weight: Not disclosed
First-person pronoun: I
Second-person pronoun: you
Third-person pronoun: -san
Everyone calls me “Yamauchi-san.”
I’m a character who uses polite language.

Nagisa Umino has a bright, positive personality that always puts those around her at ease. She’s so warm and approachable that she’s even introduced as part of the “Umino Trust Healing Duo (healing specialist).”
Past: In episode 3, we saw her private side—her past as a housewife—when she flew into a furious rage upon learning that her husband had been unfaithful, letting out a deep sigh and falling into despair.
Age: 59 years old Height: 158 cm Weight: 51 kg
First-person pronoun: I
Second-person pronoun: you
Third-person pronoun: -san
Everyone calls her Kazama-san.
She’s a character who uses polite language.