Dr. Julius Reichwein is a German psychiatrist and a former lecturer at the University of Düsseldorf's medical school. Born in 1937 in Kaufbeuren, Bavaria, his background is notably diverse before he settled into his career as a healer of the mind. He initially studied medicine, majoring in plastic surgery in Munich, before serving his conscription and joining the police force. His service as a surgeon for the West German border guard, which he did for twelve years on the Czechoslovakian border, gave him a unique combination of discipline and hands-on experience very different from a typical academic's life. After leaving the guard at age forty, he pursued psychology and became a lecturer at Düsseldorf, where he taught students who would become some of the era's most prominent medical figures, including Dr. Kenzo Tenma and the forensic psychologist Rudy Gillen. At the time of the story, he is in his early sixties, having retired from teaching to open a small private practice in Munich.

In terms of personality, Dr. Reichwein embodies the archetype of the "wounded healer" who has channeled his own experiences into compassion for others. He is an old man with a sharp mind and a resilient spirit, possessing a profound sense of empathy tempered by rigorous scientific discipline. He is a practical and grounded individual, a "great grandfather" figure who presents a calm, stable presence even when confronting the darkest aspects of human nature. Unlike many characters in the story who are haunted by personal secrets, Reichwein's strength comes from his integrity and emotional balance. He is courageous and refuses to be intimidated by powerful or dangerous individuals, as shown when he physically confronts hired thugs and stands his ground against the killer Roberto. Despite his professional wisdom, he is not without his own small struggles, such as a fondness for weisswurst and a personal battle with his own inclination toward alcohol, which makes him deeply relatable and human.

Dr. Reichwein's motivations are primarily rooted in his professional ethics and personal loyalty. He becomes a central figure in the struggle against Johan Liebert not out of a desire for glory, but from a deep-seated need for truth and justice. The catalyst for his involvement is the death of his friend and patient, the private detective Richard Braun. Refusing to accept the official ruling of suicide, Reichwein uses his deductive skills to uncover the manipulation that led to Richard's death, thus learning of the existence of Johan. His mission quickly expands from avenging a friend to protecting the innocent and proving the innocence of his former student, Dr. Tenma. He acts as a logistical and moral anchor for Tenma's support network, transforming his office into a safehouse and a base of operations for those trying to stop the "monster". His ultimate goal is not just to stop Johan, but to ensure that Tenma does not have to become a killer to do so, preserving the integrity of the man he believes in.

Throughout the story, Reichwein plays the crucial role of the rational ally and mentor. While Dr. Tenma is on the run, Reichwein operates openly, using his professional reputation to investigate Johan and provide a legitimate front for their activities. He serves as a crucial bridge between different factions, including the police inspector Lunge and the fugitives, and uses his contacts to coordinate the efforts of the scattered allies. His key relationships form the backbone of the resistance against Johan. His professional and personal bond with Rudy Gillen is vital; the two former student and teacher collaborate closely, sharing information and analyses to try to understand Johan's psychology. His relationship with Dr. Tenma is one of mutual respect, where he offers the younger doctor not just shelter but also emotional support, reminding him that he is not alone in his fight. He also becomes a surrogate guardian to the young boy Dieter, providing the stable, loving home that the child desperately needs, and he cares for other non-combatants like the broken Eva Heinemann, helping her through her alcohol withdrawal and guiding her toward a path of rehabilitation.

Dr. Reichwein undergoes significant development, transforming from a semi-retired therapist into an active, hands-on investigator and protector. Initially, he is a concerned clinician grieving a lost friend. As he digs deeper into the conspiracy, he sheds his passive role and becomes a determined operative, even risking his life in physical altercations. However, his core identity never wavers; he remains a healer. His development is less about changing who he is and more about the full expression of his latent strength, courage, and moral clarity in the face of overwhelming evil. By the story's end, he has successfully guided many of the broken survivors through their trauma, including Eva, and continues to care for Dieter, symbolizing the restoration of humanity and hope after the chaos.

Regarding abilities, Dr. Reichwein is far more capable than his age might suggest. Professionally, he is a highly respected psychoanalyst with decades of experience in treating addiction and trauma, giving him incisive insight into the darkest corners of the human mind. This allows him to identify Johan's methodology of psychological destruction where others see only random tragedy. Physically, his past as a border police surgeon has left him with formidable self-defense skills; he holds black belts in both karate and judo, a fact that surprises those who mistake him for a frail old man. This combination of psychological expertise, physical resilience, and unwavering moral conviction makes him one of the most effective and grounded characters in the narrative, a true pillar of reason in a world descending into nihilism.