Genta Kojima

Genta is energetic, impatient, boastful, and extremely food-motivated. He regularly interprets monetary values in terms of how many bowls of unagi they could purchase and is easily distracted by the prospect of a meal.

He declares himself leader of the Detective Boys, although Conan generally directs the group whenever a genuine investigation develops. Genta can become jealous or competitive when his authority is challenged, but his leadership claims are more childish bravado than serious hostility.

Despite his lack of caution, Genta is brave and loyal. He does not deliberately abandon his friends when situations become dangerous and can act decisively when another child needs help.

Genta has no extraordinary abilities. His large build gives him greater physical strength than Ayumi and Mitsuhiko, though his lack of discipline means he is not a trained fighter.

He participates actively in searches using the Detective Boys equipment created by Hiroshi Agasa, including communication badges and flashlight wristwatches.

Genta's investigative reasoning is less developed than Conan's or Mitsuhiko's, but his direct observations occasionally produce useful clues. His tendency to say exactly what he notices can inadvertently point Conan toward an important contradiction.

Genta is one of Conan's first classmates after Shinichi assumes his child identity. He and Ayumi initiate the exploration of an allegedly haunted mansion, dragging the reluctant Mitsuhiko and Conan into what becomes one of the children's earliest investigations.

The later Italian gold case exposes Genta and the others to genuinely dangerous criminals. Rather than discouraging him, the experience helps inspire the formation of the Detective Boys.

Genta remains one of the group's most consistent members throughout the series, accompanying Conan on investigations, camping trips, treasure hunts, and outings that frequently become criminal cases.

Conan Edogawa is Genta's friend and teammate. Although Genta calls himself the Detective Boys' leader, Conan Edogawa usually provides the reasoning that guides their investigations.

Ayumi Yoshida is Genta's classmate and one of his closest friends.

Mitsuhiko Tsuburaya is another close friend and fellow founding member of the Detective Boys.

Ai Haibara joins Genta's class and becomes part of the Detective Boys despite initially keeping the group at a distance.

Genji Kojima is Genta's father. Genta resembles him physically and shares some of his forceful personality.

Hiroshi Agasa regularly supervises Genta and the other Detective Boys outside school.

Sumiko Kobayashi is Genta's teacher and one of the adults responsible for his class.