Masaya Horii is a supporting character in the anime Massage Parlor Pervert. He is a Japanese man of average appearance, with black hair and grey eyes. He works as a senior office employee, and it is later revealed that he is a co‑worker of Yuzuki’s fiancé.

Horii initially appears as a regular customer at the massage parlor where Yuzuki works. On her last day before retiring to marry, he openly begs her for extra personal services beyond the normal massage, which she firmly refuses. After Yuzuki leaves her job, Horii is invited to her and her fiancé’s home for dinner, having concealed his identity as a former customer. During the visit, while the fiancé is passed out drunk, Horii seizes the opportunity to force himself on Yuzuki, using his position as a trusted colleague of her husband to gain access.

His primary motivation is sexual gratification, and he acts with persistent, manipulative, and predatory behavior. He shows no remorse for exploiting the trust of both Yuzuki and his co‑worker. Horii’s role in the story is that of an antagonist who creates a central conflict by threatening Yuzuki’s new married life. He has no notable special abilities; his power lies in his social position and deceit. The character does not undergo any meaningful development or change over the course of the narrative, remaining a static, opportunistic figure throughout.