Kenjirō Toki is the editor responsible for the light novelist Itsuki Hashima in the anime A Sister's All You Need. His primary function within the narrative is to act as the professional anchor for Itsuki, whose habits as a writer are often chaotic and undisciplined. Toki spends a significant portion of his time and energy tracking down his elusive author, who frequently disappears on what he calls research trips, which are often a cover for procrastination. This requires Toki to possess the persistence and resourcefulness of a detective, as he follows Itsuki to various locations to ensure that deadlines are met and that manuscripts are eventually submitted.

In terms of personality, Toki is characterized by his professionalism, patience, and dedication. He maintains a composed attitude despite the considerable stress that comes from managing a writer who is prone to distraction. Toki successfully balances the role of a strict disciplinarian with that of a supportive fan. He does not simply view Itsuki as a client or a source of work; he genuinely appreciates the craft and is an avid reader of the stories his author produces. It is noted that he takes great pleasure in being the first person to read Itsuki’s new manuscripts before anyone else, a testament to his sincere enthusiasm for the work itself beyond his editorial duties.

His role in the story is fundamentally that of a supporting character who enables the professional activities of the main cast, particularly Itsuki. As an editor, he represents the industry and the practical demands of being a professional writer, contrasting with the more fanciful or self-indulgent tendencies of the creators he works with. Regarding his relationships, his primary and most significant connection is with Itsuki Hashima. The dynamic between them is one of mutual dependence, where Itsuki relies on Toki for structure and guidance to stay on track, while Toki relies on Itsuki for the creative work that is central to his professional life.

Toki does not undergo a significant personal transformation throughout the series, as his role is more about providing stability for the other characters. His development is subtle, rooted in the deepening mutual respect and understanding within his working relationship with Itsuki. As for notable abilities, his most impressive skill is not a supernatural or physical power, but his remarkable talent for locating and corralling a writer who is actively trying to avoid work. His ability to manage and motivate a difficult creative personality, combined with his organizational skills and encyclopedic knowledge of deadlines, makes him exceptionally good at his job.