OVA
Description
Professor Hiroshi Agasa, universally called "Professor" or "Professor Agasa," is a central supporting character. This 53-year-old inventor lives next door to the Kudo family. He attended Teitan Elementary School and later Okuho Middle School, where he met his first love, Fusae Kinoshita, in sixth grade. Fusae moved away during the fall term, and Agasa's family soon relocated from Tokyo to the countryside. Decades later, they reunited, with Fusae now known as Fusae Campbell, a successful fashion designer. His family includes deceased parents, a deceased great-uncle named Kurisuke Agasa (an enthusiast of gadgets), and a deceased great-aunt, Teiko Agasa, plus an unnamed cousin and a cousin's granddaughter.

Jovial, caring, and outgoing with a wide social network, Agasa helps conceal the true identities of Conan Edogawa and Ai Haibara by presenting them as children of acquaintances. He holds at least one advanced degree and possesses high intelligence, though many of his inventions fail or cause destruction. However, several gadgets—like the Voice-Changing Bowtie, Detective Boys' badges, and flashlight-watches—prove invaluable. His creations have been used in official events, and patents, including video games tested by the Detective Boys, fund his comfortable lifestyle. Paternal towards the Detective Boys, he often accompanies them on trips that unintentionally involve criminal cases. He enjoys pasta and tomato juice and displays remarkable luck winning food prizes.

Agasa's significance stems from being the first confidant of Shinichi Kudo after the APTX 4869 transformed him into a child. He advised caution against the Black Organization, helped establish Shinichi's alias as Conan Edogawa, and enrolled him at Teitan Elementary, leading to the Detective Boys' formation. Later, he discovered Shiho Miyano (Ai Haibara) collapsed near his home after escaping the Black Organization. He took her in, learned her identity, and aided her new life as Haibara. Agasa also informed Shinichi's parents, Yusaku and Yukiko Kudo, of their son's condition. His relationship with Haibara is distinctive; she often acts protectively or maternally, regulating his diet and shielding him from danger. Agasa knew Haibara's parents, Atsushi and Elena Miyano, particularly her father, though unaware they had children.

Agasa owns an unreliable yellow Volkswagen Beetle prone to breakdowns, featuring a built-in television. He once possessed a valuable Persian rug involved in a theft case that prevented its sale. In the OVA "Excalibur no Kiseki," he collaborated with an old friend, a baseball coach, to devise a plan inspiring a struggling young player, Minae. They planted a baseball bat in the field, referencing King Arthur's legend, to boost her confidence. Agasa enlisted Conan's help to soften the soil around the bat discreetly and prevent its removal. This subplot involved the Detective Boys and police detectives Takagi and Chiba, who initially suspected Agasa and the coach of jewel theft.

Agasa has a mole on his buttock with a protruding hair, revealed by Conan to prove his identity. He was erroneously voted "most likely to be the Black Organization's boss" in a fan poll, though the series' creator confirmed this untrue. His name derives from Agatha Christie, with "Hiroshi" (博士) punning on "hakase" (professor). His great-uncle and aunt, Kurisuke and Teiko, are named after the Japanese pronunciation of "Christie".