OVA
Description
Melo is the nickname of Meroune Lorelei de Neptune, a central character introduced as the fifth non-human exchange student to reside in the host household. She is the legitimate royal heir to the merfolk kingdom, a status she carries with a natural sense of grace but not overwhelming arrogance. Her arrival is orchestrated by the exchange coordinator Kuroko Smith, who places her in the home without prior notice to the host, Kimihito Kurusu. Due to her lower body being a large, elegant fish tail, she cannot walk on land and navigates daily life using a specialized wheelchair, which is later upgraded to a motorized version. Her personal living space is a pool room built to accommodate her aquatic needs, though it often becomes a popular spot for other characters to relax.

In terms of personality, Melo is characterized by her gentle, polite, and composed demeanor. She often acts as a voice of reason and a calming presence among the more boisterous personalities in the household. However, this serene exterior hides a deeply romantic and dramatic inner world. She is famously obsessed with tragic romance stories, particularly the fable of the mermaid princess, which has shaped her belief that true beauty in love is found in sorrow, unrequited longing, and melancholy. This leads her to frequently lose herself in daydreams about doomed love affairs, often casting herself in the role of the tragic mistress rather than the primary partner. Despite her delicate appearance, she possesses surprising physical capabilities, including immense strength in her tail and high agility in water, which she occasionally demonstrates on land with a powerful tail swipe.

Melo's primary motivation is her search for a love story worthy of her tragic ideals. Initially, she pursues the role of Kimihito’s tragic mistress, hoping to experience the beautiful pain of an impossible romance. She genuinely desires to be part of a dramatic love triangle, finding the concept of being the secret, sorrowful lover more appealing than being a happy bride. As the story progresses, her motivations evolve. While she never entirely abandons her love for melodrama, her feelings for Kimihito become more earnest and direct. She transitions from wanting to be a secondary figure to openly vying for a primary place in his heart, though she still occasionally tries to recruit the other girls into a "mistress club" to fulfill her dramatic fantasies.

Her role in the story is primarily that of a mediator and a source of high-class, dramatic comedy. She frequently steps in to diffuse conflicts between other household members, using her polite logic to bring peace. Simultaneously, her morbid fascination with heartbreak creates many humorous situations, as her wild romantic ideas often baffle or exasperate the other characters. Her dynamic with Kimihito is defined by her respectful address of him as "Master" and her initial desire to be a secret lover. Over time, this relationship deepens into a more genuine affection, though her dramatic flair remains a constant filter for her interactions. She shares a cordial relationship with the other residents, enjoys a mutual respect for nobility with Centorea Shianus, and has a nurturing, if sometimes bewildering, friendship with the rest of the girls. She is also close enough to the MON squad that they frequently use her personal pool as a break room.

Melo undergoes notable character development, shifting from a girl who romanticizes the pain of being the "other woman" to one who openly declares her love and strives to be the number one person in Kimihito’s life. This growth is spurred by her daily life and experiences with the host family, which teach her that real, present affection has value beyond fantasy. Despite this development, her core personality remains intact; she continues to view the world through a lens of literary romance, ensuring that her behavior is always tinged with a touch of elegant, humorous tragedy.

Her notable abilities are tied to her physiology as a mermaid. She is an exceptionally fast and agile swimmer, capable of leaping high out of the water. On land, despite her reliance on a wheelchair, her tail is a formidable weapon, capable of knocking out smaller individuals with a single blow. Her skin is constantly covered in a protective layer of mucus to prevent it from drying out, a trait that makes her resilient in cold conditions but also causes her specialized swimwear to occasionally slip, leading to comic mishaps. As royalty, she receives a generous allowance, which she dutifully hands over to Kimihito to help cover household expenses.