Dr. Julius Reichwein is a German psychiatrist and a former lecturer at the University of Düsseldorf Medical School. Born in 1937 in Kaufbeuren, southern Bavaria, he originally majored in plastic surgery in Munich before serving his conscription and joining the police force. He spent twelve years as a police surgeon for the German Border Guard on the Czechoslovakian border before leaving at age forty to study psychology, eventually becoming a university lecturer. During his time as a professor, he taught Kenzo Tenma and Rudy Gillen, both of whom he held in high regard for their dedication and academic excellence. He later retired to Munich, opening a small private practice specializing in counseling for alcohol dependence.

In his personal history, Reichwein is a portly older man with balding gray hair, a prominent horseshoe mustache, and browline glasses. Despite his advanced age, which is around his early sixties during the events of the story, he possesses a remarkably resilient constitution, a remnant of his years as a military surgeon. He is a widower who returned to Munich to claim an inheritance after his father's death at age fifty, which he used to fund his current practice. His secretary, a somewhat absent-minded woman named Merez, assists him in his daily operations.

Reichwein is defined by his deep well of empathy, which is tempered by a rigorous scientific discipline and decades of professional experience. He has witnessed the most damaging aspects of human nature through his patients but has maintained an unshakeable faith in the capacity for redemption. Unlike many characters consumed by personal secrets or vendettas, Reichwein is emotionally stable and grounded, operating as a voice of reason. He is pragmatic and courageous, refusing to be intimidated even when facing violent killers. He also struggles with his own personal challenges, including a tendency to rely on alcohol, though he actively works to manage this trait. His strength lies in his ability to listen, to heal psychological wounds, and to serve as an anchor of civility and moral logic in the midst of chaos.

Reichwein enters the central narrative through his relationship with Richard Braun, a former detective and his patient. When Richard is found dead in what police rule a suicide, Reichwein becomes immediately suspicious. He knows Richard was making progress in his recovery and that the bottle of whiskey found at the scene was a brand Richard despised and would never drink. Driven by a need for justice for his friend, Reichwein begins his own investigation. This quest leads him to uncover the manipulations of Johan Liebert, revealing how Johan psychologically destroyed Richard. Reichwein courageously confronts the wealthy Hans Georg Schuwald to warn him about Johan, who is acting as his secretary. This puts him directly in the crosshairs of Johan's forces, specifically the operative Roberto, who attempts to assassinate Reichwein. During a tense confrontation in his own office, Roberto reveals his connection to Johan, forcing Reichwein to flee and eventually be rescued by Dr. Tenma. This event solidifies Reichwein's role as a key ally, transforming his clinic into a sanctuary and operational hub for those pursuing the truth about Johan.

Reichwein has several crucial relationships that define his role. His connection to Dr. Kenzo Tenma is one of mutual respect, with Reichwein acting as a mentor and steadfast supporter, protecting Tenma's reputation and providing him with logistical support. He is a close colleague and friend to Rudy Gillen, another former student, and the two frequently collaborate on their parallel investigations into Johan. He becomes the adoptive guardian of Dieter, a young boy traumatized by the events surrounding Johan, providing him with a stable and loving home, which represents one of the storys few examples of an unambiguously hopeful and healing environment. He also offers his professional help to Eva Heinemann, helping her through her severe alcoholism and personal degradation, which in turn allows her to regain her dignity and later provide crucial testimony.

Throughout the story, Reichwein develops from a concerned psychiatrist investigating the suspicious death of a friend into a central figure of resistance against nihilism. He demonstrates significant courage, physically fighting off thugs hired to kill him and later surviving a direct assassination attempt by Roberto. His understanding of Johan evolves from a clinical curiosity to a full awareness of the young man as a profound existential threat. In the end, Reichwein survives the ordeal and is shown in the epilogue as Dieter's guardian, having successfully maintained his integrity and humanity. He serves as the memory keeper for those who fell, like Richard Braun, and represents the possibility of psychological and social reconstruction after immense trauma.

Reichweins notable abilities stem from his dual background as a physician and a psychologist. He possesses sharp analytical skills used to diagnose mental conditions and to deconstruct the methods behind Johan's manipulations. He has considerable physical resilience and basic combat capability for his age, a holdover from his military service, as shown when he subdues two younger assailants. His greatest asset, however, is his moral authority and charismatic stability; he provides a safe harbor for broken individuals and the strategic glue that holds the group of protagonists together, acting as the rational and ethical center of the story.