Watanabe

Watanabe has a strong personality but is immediately enthusiastic when he encounters Kogoro Mouri. As a fan of the celebrated "Sleeping Kogoro," he treats the detective's presence in the local investigation with considerable interest.

His most distinctive mannerism is his extremely slow style of speaking. Despite the comic effect this creates, Watanabe is a working police detective and participates seriously in the investigation around Kitanosawa.

Watanabe is an ordinary human and professional police detective. His work gives him experience with crime scenes, witness questioning and coordination with other law-enforcement personnel.

The film does not establish any exceptional combat technique or deductive ability for him. His role is primarily that of a local investigator supporting the broader police response while Conan Edogawa independently pursues the more complicated connections between the cases.

Watanabe becomes involved after the events in Kitanosawa develop into a murder investigation. He represents the Niigata Prefectural Police alongside Sasamoto, interacting with the Tokyo visitors and local residents as investigators gather information.

His admiration for Kogoro Mouri adds a comedic element to the police work, continuing the recurring series joke that law-enforcement officers often know Kogoro through his public reputation as "Sleeping Kogoro."

The investigation eventually expands far beyond the initial death, revealing connections to crimes committed eight years earlier and a plan threatening the Kitanosawa dam. Watanabe remains part of the official police presence while Conan uncovers the central conspiracy.

Sasamoto is Watanabe's fellow Niigata Prefectural Police detective and works as his assistant during the Kitanosawa investigation.

Kogoro Mouri is a detective Watanabe greatly admires because of his famous reputation as "Sleeping Kogoro."

Conan Edogawa becomes involved in the same Kitanosawa case. Although Watanabe is part of the official investigation, Conan Edogawa independently discovers many of the connections behind the crimes.