Male protagonist who becomes addicted to a transfer student's saliva, which she claims is a sign of love sickness, leading to a deep, lifelong bond.
Central couple bound by a supernatural drool exchange that synchronizes their physical sensations and emotions, evolving from accidental discovery to a deeply committed romantic partnership.
Youko acts as a protective and curious older sister, deeply involved in Akira's personal life and past.
Kouhei serves as a casual confidant and friend who offers misguided but well-intentioned advice on romance.
Urabe's initial involvement is framed by a solemn duty to protect and guide Akira, adding a layer of responsibility to their bond.
Aika pursues Tsubaki romantically and attempts to form a drool bond, creating tension that Tsubaki ultimately rejects in favor of his established connection with Mikoto.
Kouhei serves as Tsubaki's primary confidant and advisor, offering grounded perspectives on relationships while occasionally getting entangled in the supernatural dynamics.
Ayuko interacts with Tsubaki as a friendly classmate, often discussing relationship dynamics and observing his life.
Explore the full interactive character relationship map of Mysterious Girlfriend X