Karl is a dynamic, round character whose development explores how a person continues living after trauma that cannot simply be overcome. When Bertie discovers him after his escape from Dachau, he is physically devastated, guarded, and distrustful of safety after 11 years of imprisonment and abuse. His experiences have also made him unusually perceptive. He recognizes Bertie’s survivor’s guilt, challenges Sofie’s self-blame over her family, and understands that the apparent ordinariness of the Nazis makes them more frightening rather than less. At the same time, he struggles to extend similar compassion toward himself.

Karl’s character underscores the theme of The Arbitrary Nature of Survival, as he rejects Bertie’s attempts to find meaning in who lived and died. “Survival means nothing, Bertie” (122), he insists, because his own survival depended largely upon circumstances and exploitation rather than superior strength or worth. Despite his trauma, Karl remains resourceful and capable of decisive action. His improvised Jewish-family cover story saves Bertie and Sofie from Ward, while his ability to consciously manage how others perceive him repeatedly helps the family survive. However, he resents having to perform conventional masculinity, recognizing that safety continues to require concealing parts of himself.

Karl gradually becomes more willing to imagine a life beyond immediate survival. Learning to play “Das Lila Lied” on the piano provides him with a non-verbal outlet for his passion, allowing him to connect with a history of queer joy he never experienced. The song becomes a tool for reclaiming a piece of his lost heritage. At the same time, his growing bond with Bertie and Sofie gives him a new family, as he asks that all three take the surname Bauman in America and carries asparagus berries from the farm in hopes of planting them there. While he remains scarred and acknowledges that he will never fully recover, his final statement that “The history is us […] [a]nd we’ll keep passing it on” (289) captures his development: Karl never discovers a reason for why he survived, but he begins to decide what he will do with the life that remains.

Sofie is a pragmatic, resilient, and deeply compassionate character who acts as the emotional and practical anchor for the central trio. As Bertie’s partner, she shares his life of concealment in Ulm, but her perspective is often more grounded and forward-thinking. In moments of crisis, Sofie’s quick thinking is important to their survival. Her most dramatic act of ingenuity is faking a miscarriage to deceive a Nazi roadblock, a performance of such conviction that it allows her and Bertie to escape Berlin. Later, when Lieutenant Ward confronts them on the farm, she is prepared to defend them with a chair, showing a fierce protective instinct that tempers her otherwise calm demeanor. Her courage is balanced by tenderness, particularly in her ability to support the two men without dismissing their grief or trauma.

Sofie’s character is also shaped by her own history of guilt and loss. She has long blamed herself for the drowning death of her nephew and later learns that the rest of her family died during the war. Saving Karl from drowning becomes especially meaningful because she succeeds where she believes she once failed, allowing her to begin viewing herself differently. Her relationship with music is another key aspect of her character. A skilled pianist, she uses her talent as a tool for healing. By teaching Karl to play “Das Lila Lied,” she connects him to a joyful queer history he never knew and gives him a way to process his trauma. Music becomes their shared language of resilience. Though she loses her biological parents to a bombing, she dedicates herself to building a new family with Bertie and Karl. Her simple instruction to “live” in the novel’s final moments captures her forward-looking resilience, reminding the other characters and the reader that honoring those who died does not require refusing the life that remains.

Gert is Bertie’s closest friend and one of the novel’s strongest connections between its joyful prewar world and the losses that follow. In 1932, he is affectionate, playful, and optimistic, celebrating his surgery, relationship with Roy, and American citizenship while openly participating in Berline’s queer community. His exuberance contrasts with the increasingly dangerous political environment. By 1934, however, the carefree Gert has become acutely aware of that danger. When the Nazis begin targeting people on their lists, he risks himself to warn Bertie and Sofie, providing the plan and refuge that ultimately save their lives even though he can only reach one friend.

After his disappearance during the Night of the Long Knives, Gert becomes a haunting presence in the narrative. For Bertie, he is the focal point of his survivor’s guilt and unresolved grief. The discovery of the flat-cap and the ambiguity surrounding his death underscore the lack of closure experienced by so many survivors of the Holocaust. Gert’s memory is preserved both in Bertie’s mind and also in the name the trio ultimately adopts in America, making him a foundational part of the new family they build. Gert represents more than what persecution destroyed, as his love and choices continue protecting others after his death, allowing part of the community he belonged to to survive.

Lieutenant William Ward is the novel’s primary antagonist, a flat and static character who embodies the danger of institutional authority without empathy. An American officer participating in the occupation, Ward is suspicious, aggressive, and prejudiced toward Bertie and Sofie. He repeatedly abuses his authority while investigating them, eventually using Nazi records retained by the Americans to uncover Bertie’s identity and pursue him under laws that continue to criminalize gender nonconforming individuals. His taunting “Fräuline Durchenwald” makes his contempt particularly personal, mirroring the prejudice ideology he is supposed to be eradicating. 

Ward creates one of the novel’s primary sources of irony, a representative of Germany’s liberators who becomes a threat to people who just survived Nazi persecution. He sees himself as pursuing Nazis while failing to recognize Bertie, Sofie, and Karl as survivors of the regime he condemns. Through Ward, The Need to Protect Marginalized Groups extends beyond the defeat of Nazi Germany. His character shows how removing one oppressive government is insufficient when discriminatory laws, records, prejudices, and institutions remain capable of harming the same vulnerable people.

Dr. Magnus Hirschfeld is a mentor figure who appears in the novel’s early sections, representing the pinnacle of scientific progress and social advocacy for queer and trans people before the Nazi era. As the real-life founder of the Institute for Sexual Science, his presence grounds the story in historical fact. In the narrative, he is a kind, paternal figure who provides Bertie with a job, a home, and a sense of purpose. His intellectual and compassionate contribution is underscored by his speech about gender nonconforming individuals being the “canaries of the world,” (190) a metaphor that directly articulates the theme of The Need to Protect Marginalized Groups. Hirschfeld’s departure from Germany and the subsequent destruction of the Institut reflect the loss of both a protective institution and decades of accumulated knowledge, while his influence survives through Bertie and the people his work helped.