Shinji Inui (乾 信司 Inui Shinji) is a Sidewinder downhill driver and Go Hojo's henchmen and also a minor villain in Initial D Fifth Stage and main antagonist in the sequel stage.
Shinji drives Panda Two Tone Toyota Sprinter Trueno GT Apex 2-Door AE86. He has a calm personality and doesn't like racing. But when he gets serious, he tends to bump his opponent on purpose and make them understeer severely.
Shinji makes his debut during Project D's battle against Team Spiral. Shinji is a member of Sidewinder and therefore second driver of this team. Shinji appears to be a boy (possibly younger than Takumi) but seems very intelligent. Shinji's car is the notchback coupe variant of the AE86 Trueno (not to be confused with Takumi's Eight-Six). He is the fourth character to drive a Toyota AE86 model, after the fake Takumi's Trueno AE86. Shinji lost to Takumi, due to both cars spinning out. With the tires of Takumi's 86 locking up, it sent Takumi's 86 into a spin. Shinji had no choice but to follow. At this moment, with the experience gained from the engine blow in Akagi when going against the Evo III, Takumi instinctively presses on the clutch, freeing up the tires and regained control of the 86 momentarily. However, Takumi was going in reverse with inertia alone. Shinji, on the other hand, lacked actual dogfight experience and didn't know what to do, spinning a full 360 degree, causing him to lose more momentum than Takumi did. Takumi won by crossing the finish line backwards with his 86. Shinji's 86 ended up facing the finish line after the 360 spin. After the race in Final Stage, Shinji apologized to Hojo, Kubo, and his mother that he wasn't able to win for them. But they're weren't angry at him at all, and said that he had done enough for the team and glad that he returned safely after the fierce battle.