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, therefore he drives the 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 and a member of Thunder Fire. It is revealed during the Eight-Six battle Kyoichi states that he isn't no racing genius but his easy victories stabilises his confidence without being aware of what skills his opponents possess.
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, causing Kyoichi, the team leader, having to race the Eight-Six before the team could move on to the next opponent. It was also verbally stated that Seiji lost to Kai Kogashiwa in Irohazaka, but no actual battle was shown in the series. In Battle Stage, his Evo IV also raced Keisuke Takahashi's FD, and lost.
In Chapter 90, its revealed he is getting claustrophobic.
His Evo IV is best known for being in the World Rally Championship, driven by Tommi Makinen. Tommi used that Evo to win the championship in 1997 and 1998 briefly (although it would later be replaced by the Evo V).