Haruto Makabe is the central male character in the OVA. He is depicted as a young man living with his older sister, Arisa Makabe. His daily existence is largely defined by a domestic routine in which he is expected to perform a variety of chores and errands at his sister's direction, such as returning rented DVDs and washing her underwear. This dynamic establishes a household where he has become accustomed to a passive role, dutifully following instructions without protest.

In terms of personality, Haruto comes across as passive and somewhat uncertain, especially in contrast to the dominant and confident presence of his sister. He is not an initiator but rather a reactor to the circumstances that unfold around him. When Arisa begins to introduce a series of intimate and erotic games into their relationship, Haruto’s primary response is one of escalating astonishment. He is consistently surprised as his sister pushes the boundaries of their interactions far beyond anything he had anticipated, leaving him uncertain about the trajectory of their relationship.

Haruto's primary motivation does not stem from a personal goal but from a need to navigate the rapidly changing and confusing dynamic within his own home. He does not drive the plot forward; instead, his role in the story is to provide a perspective for the audience as the recipient of his sister's advances. The narrative focuses almost entirely on the private, evolving relationship between the siblings, and Haruto’s role is to react to and cope with Arisa's escalating behavior. The progression of events is firmly in Arisa's hands, and Haruto's journey is one of shifting from passive acceptance to a state of heightened awareness and uncertainty about their future.

The key relationship that defines Haruto is, without question, the one he shares with his older sister, Arisa. This relationship is characterized by a significant power imbalance. Externally, Arisa may present a perfect and sweet-natured facade to the world, but at home, she behaves like a queen, treating Haruto more like a personal butler. This foundation of dominance and submission sets the stage for her to later pursue a romantic and physical relationship with him, taking the dominant role as she initiates all intimate encounters. Haruto's development throughout the story is subtle and confined to this singular relationship. He begins in a state of passive obedience, but as Arisa's actions grow bolder, his awareness shifts, and he moves from simple astonishment to facing the profound uncertainty of where their new, secret bond will lead. He does not possess any notable supernatural or combat abilities, as the story is grounded in a realistic, if taboo, domestic and romantic scenario.