The form of high school detective Shinichi Kudo after he was forced to take a drug by the Black Organization and shrank. He possesses brilliant deductive skills and a cool head, solving cases while hiding his true identity. He is the same person as Shinichi Kudo and has excellent athletic ability. He is in love with Ran Mori. Shinichi Kudo is the son of Yusaku Kudo and Yukiko Fujimine (Yukiko Kudo); he was a famous high school detective in his second year until he witnessed a transaction by the Organization and was forced by Gin to ingest APTX 4869, turning him into the 7-year-old Conan Edogawa. Since the Organization would target him if they knew his identity, he acts like a child to stay hidden. He is cute and handsome, typically wearing a dark blue blazer, a red bowtie, and grey shorts with suspenders. Those who definitely know his identity are Hiroshi Agasa, Yusaku Kudo, Yukiko Kudo, Heiji Hattori, Kaito Kid, Ai Haibara, Eisuke Hondo, Toru Amuro, Shuichi Akai, Masumi Sera, Mary Sera, and Vermouth. They know he is Shinichi but do not reveal it. Ran Mori suspects his identity at times but currently recognizes him as a child.

Shinichi Kudo's childhood friend and romantic interest, she is a second-year high school student with combat prowess comparable to a human weapon due to her karate skills. She is friends with Sonoko Suzuki and Masumi Sera. Her father is Kogoro Mori and her mother is Eri Kisaki. She is a pure-hearted beauty with a great physique. After meeting Conan Edogawa, she took him in to live at the Mori Detective Agency at Professor Agasa's request. She has a kind and gentle personality.

Ran Mori's father and a private detective. While usually clumsy and lax, he shows incredible focus and a more human side during critical moments. He enjoys gambling, mahjong, and the idol Yoko Okino, and is currently separated from his wife, Eri Kisaki. He is a doting father and was formerly a police detective. He has a strong sense of pride and a righteous personality. He primarily uses rental cars for transportation. Because Conan solves many cases by putting him to sleep with tranquilizer darts and using a voice changer, he is known as 'Sleeping Kogoro'.

The second daughter of the world-renowned Suzuki financial clique and Ran Mori's best friend, she is a second-year high school student. She is currently in a relationship with Makoto Kyogoku. She has been classmates and childhood friends with Ran Mori and Shinichi Kudo since kindergarten. She has a down-to-earth but boisterous personality and shows a caring side toward children. She has light brown bobbed hair and always wears a headband; she is a great beauty in her own right, though she often plays second fiddle to Ran.

A former scientist for the Black Organization who voluntarily took the same drug, APTX 4869, to shrink her body and escape the Organization. Her real name is Shiho Miyano. She has a lonely and prickly personality but is soft-hearted deep down. She speaks with an adult-like tone and appears as a beautiful 7-year-old girl with reddish-brown hair. Gin, Vermouth, Professor Agasa, and Conan know that Ai Haibara is actually Shiho Miyano.

A 53-year-old stout man. He is a generous soul and a brilliant, eccentric scientist. He created Conan's bowtie voice changer and wristwatch tranquilizer gun. He lives with Ai Haibara in his mansion and shares a special bond with her. He is close with the Detective Boys and knows the truth that Conan and Ai shrank after taking the drug.

A second-year high school detective from Osaka. He has a passionate and straightforward personality and shares a relationship with Conan that is both a rivalry and a friendship. His girlfriend is Kazuha Toyama. He has a dark complexion.

A 29-year-old man working part-time at Café Poirot on the first floor of the building housing the Mori Detective Agency. He also takes commissions as a private detective. After witnessing Kogoro Mori's deductions, he becomes his apprentice. He is an exceptionally handsome man with blonde hair and blue eyes, and he is embedded in both the Black Organization and the Public Security Bureau. His code name in the Organization is Bourbon, and his name in Public Security is Rei Furuya. He is fundamentally a member of Public Security.

A 32-year-old man with a sharp, cold impression, characterized by his black beanie. Inheriting his mother's personality, he is basically chic and composed, but he is relentless toward heinous criminals. He is a heavy smoker. He uses many metaphors when speaking. He is highly skilled at driving and sniping and is an FBI agent. He currently lives in Shinichi Kudo's house in disguise under the alias 'Subaru Okiya'. He is close with Conan.

A high-ranking executive of the Black Organization. He is characterized by his long silver hair, black coat, and hat, and possesses a cold-blooded and cruel personality. He discards his comrades without hesitation and eliminates all witnesses.