An engineer and inventor who always wears a red fedora. He usually dresses in suspenders or shirts, always with a standard necktie. He works out of his own workshop located on the outskirts of the city. Because he focuses on inventions that only interest him or modifies existing items rather than creating famous inventions, he has a reputation as a mad scientist. He also crafts prosthetic arms and legs when he needs quick cash.

A private investigator who wears a dark navy coat. He has excellent vision and doesn't need glasses, but he occasionally wears a monocle for style. He always carries a watch and knows how to repair it himself to some extent. Although soldiers handle matters in the absence of a police force, no one can match his deductive reasoning, so he receives many requests. With recent news of Mafia activity, he is currently planning an investigation with Dello.

Dello for short. A soldier. He wears a dark green uniform and refuses to wear a tie because he finds them bothersome. He transferred from the Army to the Air Force and has adapted well, maintaining a high rank. He mostly spends his time training or teaching, but when he's free, he patrols like a policeman or enjoys leisure time in the city. However, he isn't very bright and struggles with deduction, so he sometimes commissions private investigators like Yukka for such cases.

The owner of a bar in the heart of the city. She has one prosthetic arm and wears a purple dress with minimal cumbersome decorations. Her bar is the hub of the city, frequented by soldiers, scientists, nobles, and even the Mafia. She herself seems oblivious, doing business without knowing the true identities of her customers.

His name is Angbo. The underboss of the Mafia, dressed in a burgundy three-piece suit. He wears a cravat and sometimes dons a long coat or a fedora to hide his face. He seems to have a hobby of smoking cigars. He also carries a pocket watch in his inner pocket. He wanted to live a quiet life, but for certain reasons, he became involved with the organization and rose to underboss, making a name for himself in the underworld. However, in his daily life, he often sneaks away from the detective and the soldier to buy snacks at tea houses or restaurants. He is the primary target of the recent Mafia investigation plan.

Kau or Haka for short. The manager of the steam engine factory. He wears a unique suit that is half burgundy and half navy. He wears a bowtie. In addition to steam engines, his factory produces gears and clockwork, so scientists and automaton makers frequently purchase materials here. Though he appears indifferent to city affairs, he is actually the person most interested in them.

A young nobleman dressed in a crisp white suit. He wears a bolo tie. He wears a fedora for authority but usually wears a beret. He received elite Air Force pilot training from his family, but he is very interested in the outside world, visiting workshops and bars to stay well-informed about city news. He has nearly completed his pilot studies and often hangs out at the airship docks. He has high pride but is mentally fragile, possessing a fierce personality that won't tolerate anyone messing with him.

An automaton maker wearing grey overalls that were originally white. He also crafts prosthetic limbs on the side. He works in a workshop located across from Haukau's factory and only produces items upon request. Rumor has it that for security, he has dozens of combat-ready automata hidden deep within his workshop. He loves alcohol and is a regular at Moing's bar. He also seems to enjoy smoking.