The Professor, a reclusive scientist and informant, recurs as a supporting figure with expertise in pharmaceuticals and biotechnology. Decades prior, during Central American conflicts, he provided medical aid to combatants. There, he encountered a young Ryo Saeba suffering severe withdrawal after forced administration of the combat drug Angel Dust. The Professor treated Ryo successfully, saving his life over an extended recovery and establishing a lasting debt of gratitude. He maintains a concealed Tokyo laboratory, functioning as Ryo Saeba's knowledge resource. His scientific acumen spans immunology and experimental technologies, prompting him to employ immunologist Kazue Natori as his assistant after her involvement in a case concerning genetically modified bees. Primarily, he provides critical intelligence; for example, he deciphered the Mobius system—a neuro-linked weapons control platform developed by Iris Woods's late father—and identified Iris as its activation key during the Shinjuku Private Eyes investigation. Mutual respect and trust define his relationship with Ryo, forged through their shared past. He offers expertise without fieldwork, focusing on analysis and information dissemination, while his lab serves as a safe haven. Though his past actions demonstrate significant medical skill countering toxins like Angel Dust, his current activities center on researching contemporary threats. Kazue Natori's role as his assistant underscores his ongoing focus on specialized biological sciences and his practice of mentoring younger scientists. Their collaboration follows her resolution of a personal conflict involving stolen biotechnology, indicating he provides a legitimate outlet for her skills. Operating off-screen yet pivotally, he enables key revelations that advance investigations, particularly technological conspiracies requiring scientific explication.