Ramune is a physician specializing in "mystery diseases" – physical manifestations triggered when something "strange" invades a patient's mind due to emotional or psychological distress, conditions untreatable by conventional medicine. He possesses blond hair and yellow eyes, typically dressed in a white robe secured by a purple belt and sandals.

His personality is lively and childlike, often appearing unserious or insensitive. He cracks jokes, teases impulsively, and frequently misreads social situations, leading to unintentional rudeness. Despite this outward demeanor, he holds deep compassion for patients and friends, demonstrating self-sacrificial tendencies like suffering a broken arm to rescue a patient. He harbors a pronounced fear of his former mentor, Momiji, who often torments him.

Professionally, Ramune excels at rapidly identifying the root causes of these diseases, usually stemming from suppressed emotions or unresolved conflicts. However, his treatment philosophy prioritizes patient autonomy; he provides "mysterious tools" to aid healing but encourages patients to confront their underlying issues independently. This approach, sometimes appearing lazy or indirect, reflects his belief in avoiding harsh interventions and fostering self-resolution.

He works closely with Kuro, his junior high school-aged apprentice and assistant. Kuro compensates for Ramune’s impulsiveness with rational judgment and a stoic demeanor, acting as the stabilizing force in their dynamic. Ramune deeply trusts and relies on Kuro during treatments.

His connections extend to Ayame and Nico, who run the "Mysterious Wares Shop Akatsuki." Ayame, a 112-year-old who appears as a child, crafts the mystical tools he uses. Nico, her great-grandchild, shares a brotherly bond with Ramune.