TV-Series
Description
Hans Kleif is a fictional character appearing exclusively in the anime series A.D. Police: To Protect and Serve. He serves as an officer of the A.D. Police, the special law enforcement unit tasked with handling crimes involving out-of-control robots known as boomers.

Originally from Germany, Kleif was transferred from the regular police force to the A.D. Police in Tokyo, where he becomes the new partner of the notoriously difficult detective Kenji Sasaki. His physical appearance is that of a young adult male with blond hair and blue eyes. Kleif carries a secret he is initially unaware of: following an accident where a piece of shrapnel became lodged in his brain, he lost all memories of his past, a condition that contributes to a deep-seated anxiety about his own identity.

In personality, Kleif serves as a stark contrast to his brooding partner. He is characterized by a laidback, friendly, and humorous demeanor, making him more approachable and easier to get along with than the reserved Kenji. He is also portrayed as a confident extrovert who speaks his mind, a trait that initially leads to friction between the two partners before they gradually develop a strong mutual trust and friendship. Throughout the story, he becomes involved in a romantic relationship with Yuki Satomi, a woman who is later revealed to be a Genom official posing as his nurse.

Kleif's role in the narrative is defined by his partnership with Kenji. The two are forced to work together to investigate and stop Liam Fletcher, a dangerous black-market cyber-criminal. As the series progresses, Kleif becomes increasingly troubled by his amnesia and confides his anxieties about his past to Kenji, demonstrating the deep trust that has formed between them. The central tragedy of his character arc is the revelation that he is not human at all, but an artificially created bio-fused boomer, an improved version of an earlier model like his adversary, Liam Fletcher. The memories he believes he lost were likely entirely fabricated as part of an experimental program.

This discovery is devastating for Kleif. Fearing the loss of his remaining humanity, he makes Kenji promise to kill him if he ever loses control and becomes a feral boomer. In the final episodes, his condition worsens, and he begins a fatal transformation. In the climactic confrontation, having lost control of himself but determined to prevent the villain Kaibara from escaping, Kleif forces his trusted partner and friend, Kenji, to fulfill his grim promise by killing him, thus destroying both the boomer and his human identity.

As an artificially created being, Kleif possesses notable abilities beyond those of a normal human. This is most prominently demonstrated after he suffers a severe injury in a fight with a rogue boomer; although the wound seems fatal, he heals at an unnaturally rapid rate, sparking Kenji's suspicion about his true nature. His full power is unleashed in the series' finale when, accepting his identity, he willingly transforms into a powerful, monstrous boomer form in a last-ditch effort to stop the enemy.