Meru is a supporting character in the series. She is a merrow, a type of mermaid from another world, who travels to Earth. To maintain a human form while on Earth, she relies on a special potion called MAXI-MAN IMPACT. In her human form, Meru is unable to swim, and she has a dislike for salt water. She enjoys eating fish and speaks with a cheerful demeanor, adopting a fake accent that she believes suits her personality; this accent is often described as a playful Kansai dialect. Her role in the story is as one of the various mythical beings who come to the human world and seek help from the main character Tomoatsu Naoe, a massage therapist and dietician. Meru works at a fish shop called Gamu Fisheries. Due to the modern lifestyle on Earth, which offers fewer opportunities for swimming, her upper arms have become somewhat flabby, a condition that becomes part of her character. She is generally bright and good-natured, contributing to the series' comedic and supportive ensemble. Her motivations center on navigating life on Earth while maintaining her human disguise, and she interacts with the other fantasy characters and Naoe in a friendly manner. Her notable abilities include her natural merrow traits, though in her human form she loses her swimming capability. Throughout the series, she does not undergo major dramatic development but remains a consistent, cheerful presence in the group.