Kurtz stands notably short with light blond hair parted right and blue eyes, leading to frequent misidentification as a middle or high school student despite being over 20. His physical build belies surprising strength, proven when he overpowered and pinned his larger superior, Ugaki.

Personality-wise, Kurtz displays childlike tendencies, openly defying Ugaki’s instructions unless rewarded with takoyaki, and exhibits a carefree, easily distracted nature—especially when eating. He struggles profoundly with deception, marked by stuttering, pauses before responses, and transparent facial expressions that betray his true feelings. This gullibility surfaces when he accepted Yuusuke Satake’s explanation about Sakie Satō, prompting Kurtz to return confiscated photos. He is forgetful and accident-prone, often misunderstanding assignments or neglecting tasks.

Professionally, Kurtz serves as Ugaki’s junior detective. Ugaki acts more as a father figure than a strict superior, frequently scolding Kurtz for mishaps. Their dynamic includes assignments like monitoring a drinking party involving Tetsuo Takahashi and Sakie Satō, though Kurtz caused a disruption by getting drunk. Ironically, this incident forged a closer friendship between Kurtz and Takahashi.

Kurtz’s true nature is that of a rare male incubus, though his abilities rank exceptionally weak among demis. His sole confirmed power is complete immunity to succubus influences, earning him Ugaki’s joking titles "ultimate anti-succubus weapon" or "ultimate defense machine against Demis." He lacks typical incubus powers to charm women.

Despite his flaws, Kurtz proves observant and sincere. He intervened upon perceiving inappropriate behavior—confronting Yuusuke over Sakie’s photos—and deduced Takahashi’s hidden insecurity about pursuing Sakie despite Takahashi’s outward composure.

Kurtz is confirmed of German descent. His name, meaning "short" in German, directly references his height and is likely a surname.