Kenzō Momoi serves as the division chief of the Health and Welfare Department at the Mitsuba Ward Office. He is a long-serving civil servant with thirty years on the job, having been hired in the same cohort as Hasebe's father, with whom he was close friends. Despite his high rank and seniority, Momoi is defined by an overwhelming and long-standing shyness so severe that he refuses to appear in person before his colleagues or the public. Since at least the start of the series, he has conducted all official duties and workplace interactions through a remote-controlled, highly expressive pink rabbit plush doll that wears a blue tie, operating it as his sole avatar.

This unconventional leadership method is a direct result of his personality, as he has been described as being embarrassed to show his face since childhood. However, beneath this comical and absurd exterior, Momoi is a fundamentally warmhearted and dutiful individual who takes his responsibilities seriously. He is aware that his avatar is an embarrassing oddity to those under his charge, yet he persists in using it as a way to remain close to his team, even attempting to ride on subordinates' shoulders to foster a sense of closeness. Despite his gentle intentions, his remote presence often leads to him being ignored or mistreated. His subordinates, finding it difficult to respect a doll, have been known to stomp on him, pluck his fur, or subject him to long hours of personal complaints. He also has a habit of forcing his staff to attend drinking parties because he fears being left out or bullied.

His role in the story is that of a supporting character and the unusual boss of the main cast, including Hasebe, Yamagami, and Ichimiya. He provides a source of workplace absurdity and comic relief, while also driving certain character interactions, such as mistakenly believing Chihaya and Ichimiya are on bad terms and trying to force them to get along. His key relationships are primarily with his subordinates. He finds Hasebe to be a handful, reminiscent of his father, and is often shamed by him. He struggles to work effectively with Yamagami because her large breasts obstruct the doll's line of sight, an issue he bluntly comments on. With Miyoshi, he inadvertently triggers her complex about her height and broad shoulders by finding her easy to see under. He frequently burdens Ichimiya with unreasonable overtime.

Despite his eccentricities, a few moments hint at his hidden competence and underlying sense of duty, showing development beyond his shy persona. On one occasion when the rabbit doll broke down, he demonstrated his resourcefulness and resolve by sneaking into the ward office building during a rainstorm, wearing only a cloth to hide his face, just to deliver a key. This act proves he is capable of facing the world when absolutely necessary, even if he greatly prefers not to. Outside of work, his relationship with his daughter, Kanon Momoi, is notably warm and healthy, and he happily spends his holidays going out with her while still in his rabbit form. A notable ability is his mastery of the remote-controlled doll, which moves with unnatural realism and agility, capable of jumping and possessing surprising durability that does not break even when struck.