Seiji Iwaki

Seiji Iwaki (岩城 清次 Iwaki Seiji, known as Hawk in the Tokyopop version) is the number two driver in the Lancer Evolution-only Emperor team, driving a Lancer Evolution IV. Seiji is a driver with good racing skills, but he is rather arrogant and overconfident and occasionally imprudent. He has won many races driving for Emperor against other teams, including Takeshi Nakazato of the NightKids.

Emperor Arc
Back when Team Emperor appeared in Gunma prefecture to challenge the local racing teams, Seiji was sent out against every single one. He is known to have easily defeated a 180SX from Team Thunder Fire and Takeshi Nakazato from the Myogi NightKids among others, taking each car's team sticker afterwards, then cutting it in half and placing it upside-down on the side of his Evo's rear wing similarly to how fighter pilots would paint kill marks on their planes.

After defeating various teams in Gunma, the Emperor team then set their sights on the Akina SpeedStars, aiming to beat Akina's infamous Eight-Six. Seiji volunteered to race for the Emperor team in his Evo IV against Takumi's Eight-Six. Kyoichi was well aware that it cannot be taken lightly and Seiji was specifically told that he was to follow "Simulation 3", a plan used only when victory was not certain. Said plan translated to "stay behind opponent, and overtake near the end before reaching the finish" but he was humiliated when his overconfidence and impatience led to his downfall, leading to him being slapped by Kyoichi for his disobedience. Kyoichi then scolds Seiji for having lost the race and tells him to use his head and stop acting foolish before he set his sights to race the Eight-Six before the team could move on to their next opponent. Seiji raced against Keisuke Takahashi on Akagi, and lost.

It was also verbally stated that Seiji lost to Kai Kogashiwa on Irohazaka, but no actual battle was shown in the series.

The New Eight-Six Arc
Seiji was also a spectator for Takumi Fujiwara's race against Kai Kogashiwa at Irohazaka.

Exclusive to the anime, Seiji and Kyoichi also watched Takumi Fujiwara's rematch against Ryosuke Takahashi at Akagi, commenting on their driving skills.

Tochigi Arc
Seiji and Kyoichi Sudo then came to Tochigi to spectate the battle between Takumi Fujiwara and Tomoyuki Tachi.

Kyoichi Sudo
He is his best friend whom he helped create Team Emperor. Kyoichi helped established confidence in him in his races with given strategies. But during his race against Takumi, he was slapped as he disobeyed the Simulation 3 strategy resulted in defeat.

Itsuki Takeuchi
During their scouting in Akina, he asked him for directions. After giving the information, he asked him whom Akina's fastest is. He mocked him after doubting an old Eight-Six wouldn't be worth a challenge. But was later convinced by Kyoichi to race him later on after Kyoichi heard from Ryosuke losing to him which confirms Itsuki's information was correct.

Takeshi Nakazato
Before he raced Takumi, Nakazato was his opponent during their sweep. Their race was a hillclimb and defeats him with ease after using Simulation 3. Nakazato surrendered his Night Kids team sticker to him as part of the deal of the outcome of the race. Takeshi was disgusted with this after his loss.

Takumi Fujiwara
First encountered in Akina when Itsuki confronted him. At that time, he was oblivious that he was Akina's fastest. When he raced, he came to realise it was him. He was lost to Takumi in a downhill race as he disobeyed Kyoichi's Simulation 3 strategy as he was overtaken in the second last corner which resulted in a slap as well as Team Emperor's Gunma sweep shattered. However when Kyoichi beat Takumi after the engine blowout he somewhat pitied him when he stated wasn't satisfied of Kyoichi's victory.

Keisuke Takahashi
During their invasion of Akagi, Keisuke is first in line to race before Kyoichi's race against Ryosuke. The race was a set in Akagi in a hillclimb. He got overtaken in the S sections of Akagi and lost. This battle was exclusive in Battle Stage.

Kai Kogashiwa
Prior to Takumi's rematch against Kyoichi, Kai Kogashiwa defeats him in their home turf. He was bane to his existence during Takumi's battle with Kai.

Trivia

 * In the Funimation dub of Third Stage, Kenji says Seiji's name in Japanese name order (Iwaki Seiji), instead of English name order (Seiji Iwaki).