Eiji Kamiya is a character from the Kansai region who appears as a rival and significant figure in the world of highway racing. He is half-brother to Maki Kamiya, and while Maki primarily accompanies him, Eiji is portrayed as the serious and immensely gifted racer of the two. His talents are not limited to driving; he is also established as a highly skilled tuner, running his own tuning shop in Osaka called Works-R. This shop is notably affiliated with Shige, a famous exhaust maker who also supplies parts for Tatsuya Shima's Blackbird.

Eiji's path to the Tokyo highway scene is directly inspired by an encounter with Tatsuya Shima. When Shima visited Osaka in search of a new exhaust pipe, Eiji had the opportunity to witness his driving. This experience served as a powerful motivation, prompting Eiji to travel to Tokyo himself. It is during this time in Tokyo that he meets another key figure, Rikako Ota. His journey from Osaka to Tokyo highlights his primary motivation as a racer: to challenge himself against formidable opponents like Shima and to prove his capabilities on the legendary Wangan.

Works-R is the tuning shop that Eiji owns, and it is the same shop responsible for preparing the Mitsubishi Lancer Evolution driven by himself and his brother. Speculation exists that the shop may have been temporarily closed when Eiji relocated to Tokyo to pursue his racing ambitions. This dedication to the pursuit of speed reinforces his identity as someone who prioritizes racing above all else. His abilities as both a driver and a tuner make him a complete and formidable rival, capable of not only piloting a high-performance machine but also building and maintaining it to its absolute limit.