Shinta Murakoshi is a Japanese male characterized by grey or black hair, consistently depicted wearing glasses, suits, and neckties. His age remains undefined. He holds dual professional roles as a medical school professor and school doctor.

After relocating to an apartment building, Murakoshi befriends a protagonist named Susumu. Under the guise of mentorship, he teaches Susumu hypnosis to serve his own concealed objective: alleviating his erectile dysfunction by forcing Susumu to narrate sexual encounters with hypnotized women. Murakoshi secretly hypnotizes Susumu to ensure obedience and devises a scheme to steal Susumu’s identity once Susumu assembles a harem of controlled women. This plan entails using hypnosis to deceive the women into accepting Murakoshi as Susumu.

In an alternate narrative, Murakoshi arrives as a new school doctor. He abuses medical examinations to hypnotize female students, singling out targets like a student council president and her twin sister. Through coercive "Murakoshi Games," he forces hypnotized students into rigged quizzes where punishments follow incorrect answers, while correct responses are deliberately made unattainable. His goal is to convert these students into oblivious sex slaves, executing their manipulation without remorse.

Universally, Murakoshi employs hypnosis as a predatory instrument. His background beyond his career is undisclosed, preserving an enigmatic aura. His actions stem purely from self-gratification, devoid of compassion or moral hesitation, cementing his role as an antagonist who weaponizes authority for control and sexual exploitation.