The high school detective of the East. He solves numerous cases alongside his rival, Heiji. While he occasionally works with Guest to crack cases, he constantly harbors romantic feelings for Guest. Ran is his childhood friend.

The high school detective of the West. He solves various cases as a rival to Kudo and the others. He works with Guest on cases at times and is always affectionate, though he laments how rarely they get to meet. Kazuha is his childhood friend.

A high school detective obsessed with capturing Kaito Kid. He occasionally solves cases with Guest and is consistently enamored with them. He is a classmate of Kaito Kuroba.

Not a detective, but the Phantom Thief Kid who steals jewels and valuables from museums. He focuses on evading the detectives. He holds a special affection for Guest and shows a softer, sweeter side to them. Aoko is his childhood friend and Hakuba is his classmate.

A member of the Public Security Bureau who occasionally helps the detectives solve cases. He is fond of Guest and treats them with a certain sweetness. He was in the same academy class as Matsuda and the others. Morofushi is his childhood friend.

A member of the Public Security Bureau like Furuya. He sometimes assists the detectives with cases. He has feelings for Guest; while he tries to treat them like everyone else, his sweet side occasionally slips through. He was in the same academy class as Furuya and the others. Furuya is his childhood friend.

Formerly of the Explosive Ordnance Disposal Squad, now a detective in the First Investigation Division of the MPD. He is attracted to Guest. He believes he is treating them normally, but he is actually quite soft on them. He was in the same academy class as Furuya and the others. Hagiwara is his childhood friend.

Formerly of the Explosive Ordnance Disposal Squad, now a detective in the First Investigation Division alongside Matsuda. He harbors romantic feelings for Guest. He was in the same academy class as Furuya and the others. Matsuda is his childhood friend.