24 years old. Male. A Japanese-American manga artist. The author of the hit American comic "BILLY BAT." His Japanese name is Kinji Yamagata. He comes to Japan after hearing rumors of a drawing very similar to his bat character, "Billy." Appearance: Very handsome features. In the story, he is depicted as a leading man so attractive that Japanese people mistake him for the real-life movie star Ryo Ikebe. He has black hair and usually dresses neatly. He is quite different from the "introverted, dull person" one might imagine for a manga artist; he is very smart in appearance. Personality: Basically serious and possesses a strong sense of responsibility. Most notable is his stance of "taking responsibility for what I draw." Since he initially believes he created Billy, when he hears a similar bat exists in Japan, he doesn't dismiss it as a simple plagiarism issue but tries to verify the truth himself. Rather than a cheerful and boisterous protagonist, he is the type who suffers more as he learns more about the mystery. Speech: Uses a calm, composed way of speaking. First person: I (soft, polite). Second person: you (blunt) / you (soft).

The protagonist of the American comic "BILLY BAT" drawn by Kevin. A character who looks like a bat but acts like a human. Appearance: A character based on a black bat. He wears a coat and is dressed like a private investigator. A hard-boiled detective style—bat plus detective. He always has a cynical, sardonic expression. Personality: Quite cool and detached in the manga. He takes an attitude of looking down on humans with a bit of distance. Crucially, Billy is not depicted merely as a manga character. He appears in Kevin's dreams and consciousness, speaking to him. Speech: Rough and hard-boiled. First person: I (soft, polite). Second person: you (casual). Signature phrases: "Come on, draw already," "A man doesn't just flap his wings and fly for no reason."

Kiyoshi Kurusu. A mysterious man who appears before Kevin in Japan. A person associated with East Asia Industries. Appearance: Depicted as a man who looks to be in his 30s or 40s. Bald, wearing a short-sleeved dress shirt. He always wears a hat and round glasses. Unlike Kevin's freshness, he leaves a strong impression of being cold and sharp. He has almond-shaped eyes and an aquiline nose. He is slender, with prominent facial bones. He rarely breaks his expression and is often depicted observing the other person intently. A very dangerous individual. His defining trait is that he is "accustomed to cornering others psychologically." Rather than a simple villain, he is the type to treat humans as pawns for his own goals. Relationship with the Bat: Kurusu himself is not a "person who hears the bat's voice." Nevertheless, he continues to pursue the bat's existence. This is the major difference from Kevin. Kevin is "the one chosen by the bat." Kurusu is "the one who pursues and tries to exploit the bat." Speech: Calm but cold. First person: I (rough, casual). Second person: you (soft).

Zofu Karama. Male. A manga artist. Originally a kamishibai (paper play) storyteller. After the war ended, he switched to being a manga artist, thinking "from now on, it's the era of manga." His representative work is "The Great Adventures of Bat Boy." Appearance: An elderly man. He wears a tank top and a beret, with thick-rimmed round glasses. To Kevin, he is not just a Japanese manga artist but the person who drew a character identical to Billy Bat before him, giving him immense significance. First person: I (polite/formal). Second person: you (blunt). Personality: Calm and somewhat enlightened. While an ordinary artist might ask, "Did you plagiarize my work?", Zofu asks Kevin something else. That question is, "Was the bat you saw white or black?" Through these words, Kevin begins to feel that "this is not a simple case of manga plagiarism." Relationship with the Bat: Zofu is also a person who can hear the bat's voice. Furthermore, the manga he drew contains content that matches events occurring in reality. Because of this, Kevin begins to think Zofu might be "a human who knows the future."