Chief Inspector Belbeau, also known as Inspector Bellbeau or Belbo, serves as a central figure in the 1981 anime film Kyōfu Densetsu: Kaiki! Frankenstein. His position as a high-ranking law enforcement officer in Geneva places him at the heart of the story's investigation into a series of brutal, unexplained murders that terrorize the local populace. Background details about his life prior to the events of the film are not provided, but his professional role establishes him as a figure of order and authority in a community gripped by fear. He is the primary lens through which the audience views the official response to the creature's rampage, and his unique relationship to the narrative is established from the very beginning, as the story is framed by his posthumous testimony, a report he forbade from being published until after his death.

In terms of personality, Belbeau is portrayed as a man of action and determination, possessing a cunning and tenacious nature appropriate for his rank. He is driven by a professional and personal commitment to uncover the truth behind the horrifying events, embodying the archetype of the dogged lawman who will not rest until the mystery is solved. His relentless pursuit of the "Giant of Geneva" or the "Monster of Frankenstein" defines his actions throughout the film. However, his personality is not without its rougher edges. One description notes him as being somewhat insensitive, a trait shown in a scene where he conducts an investigation in the presence of a grieving child, indicating a focus on his duty that can sometimes override more delicate social considerations. There is also a slightly more human, almost bumbling side to him, as witnessed in a moment where he leaps between giant footprints to measure them, requiring an officer to catch him from falling, which adds a touch of unexpected levity to his grim pursuit.

Belbeau's primary motivation is the pursuit of truth and justice. He is not a villain or an antagonist but a representative of conventional society trying to make sense of an unconventional horror. His role in the story is multifaceted. First and foremost, he is the chief investigator, tasked with identifying the source of the mutilations and killings. This leads him to Victor Frankenstein, whom he briefly suspects of orchestrating the atrocities, creating a parallel between the official investigation and the doctor's own guilty conscience. Beyond his investigative duties, Belbeau serves a crucial narrative function as the film's framer and chronicler. His opening narration sets the stage for the tragedy, and he is present at its conclusion, providing a sense of closure as he visits the creature's grave in the final scene, observing the red scarf Emily gave to the monster blow away in the wind. In this way, his quest for the truth transcends mere police work, anchoring the story's exploration of the consequences of Victor Frankenstein's ambition.

Key relationships for Chief Inspector Belbeau are primarily professional but carry significant narrative weight. His most direct interaction is with Victor Frankenstein, as he interrogates the doctor about the deaths and shows him the giant footprints found at the crime scenes. Victor's horrified reaction to this evidence, such as dropping his teacup, only deepens Belbeau's suspicion. He leads a coordinated force of Geneva police officers, and his ultimate confrontation with the creature occurs when he and his men corner the monster in the mountains, opening fire in an attempt to put an end to the rampage. His relationship with the creature itself is indirect, defined by the hunt. He never understands the monster's tragic and misunderstood nature as the blind grandfather and Emily do, viewing it purely as a dangerous entity that must be stopped.

Character development for Belbeau is subtle but evident. He begins as a confident man of science and order, using deductive reasoning to follow clues like giant footprints and mutilated corpses. He ends the story as a witness to an unprecedented tragedy, one that his conventional methods could not fully resolve or prevent. Standing at the creature's grave, he is not triumphant but contemplative, left to grapple with the moral fallout of Victor's hubris alongside Emily and her grandfather. As his narration is explicitly stated to be published after his death, there is a strong implication that his investigation and the story he tells represent his final testament, a truth he felt compelled to share with the world only once he was no longer in it.

Regarding notable abilities, Chief Inspector Belbeau possesses the expected skills of a senior law enforcement officer. He is a capable and persistent detective, able to piece together clues from crime scenes, such as identifying the large, non-human footprints as a key piece of evidence. He is also a strategic leader, capable of organizing and commanding a police unit to hunt the creature across the mountainous terrain. While he does not possess any supernatural or combat abilities, his authority and courage allow him to stand firm in the face of a monstrous threat that terrifies the entire town.