Kengo Akechi

An extremely intelligent, elite-level police detective (superintendent), who is Kenmochi's supervisor. First appearing in "Death TV", he is presented as an arrogant and snobbish character that becomes a rival to Kindaichi in crime-solving. However, Akechi (indeliberately) not only helped Kindaichi solve the case, but also aided him out of trouble. His relationship to Kindaichi is abrasive at the least, but they have an unspoken mutual respect for each other's abilities. He often compares the crimes in Japan to his experience in Los Angeles. He is proficient in English and French.

In "The Magical Express", it's revealed that he met Reiko Chikamiya before her death, and this eventually helps Kindaichi solve the case. In "Murder at Hell's School", (disguised as a math teacher) he claimed that he had actually been a teacher in a very famous prep-school for three years. His name may be a reference to the classic Japanese detective Kogoro Akechi created by Edogawa Rampo.

(Source: Wikipedia, edited)