Gotou is the secondary antagonist-turned-true main antagonist of the anime/manga series Parasyte. He is the most powerful Parasite in Takeshi Hirokawa's organization and an experimental Parasite created by Reiko Tamura. His body is in fact composed of five Parasites, whose shapeshifting ability has advanced to the point where they can switch positions, each forming a different limb as the situation requires. Gotou is the most intelligent and skilled, and therefore is the de facto leader of the composite body.
During his first appearance when he assaulted the Yakuza, Gotou wore track shoes, gym shorts and a tank top. He had short brown hair, with a round face, and kept his eyes closed most of the time.
To hide from the authorities, he then changes his look to have a longer face with sharp features. He has a large muscular and toned physique, which is often covered in suits. In the anime, his second appearance seems older than his manga counterpart.
Towards the end of the series, Gotou transforms into a 3 meter tall monster. The outside of his body gains a gray tinge to it, and has the appearance of exposed muscle. His face becomes sharper, sporting pointed ears and a mouth full of fangs. He also has four arms and a tail of sorts, his legs become reminiscent of a dinosaurs.
Gotou is one of the more intelligent of his kind. He has shown a superiority complex over the human race, believing they are nothing but trash. He shows no remorse in combat, dismembering his opponents without a second thought. He has shown to be a patient person, waiting for his turn to attack, and even allowing Shinichi to leave, so that he may recover. Though he believes himself to be above humans, he still considers himself nothing more than an "organism." Unlike Reiko, he couldn't care less about the purpose of Parasites, saying he lives only to fight.
In his transformed state, his thoughts become more primitive, worrying solely on survival and exterminating the human race. He was also more aggressive and became easily angered in this state, something that played a part in his downfall.
As a parasite, Gotou has the basic abilities to shapeshift his head, and maximize the physical potential of the body he's controlling. he can harden his cells for offensive and defensive purposes.
Gotou's body consists of five individual parasites, and has complete control over each one. He is able to maximize the powers of each parasite, shapeshifting and utilizing them to his every whim. He has shown the knowledge of transforming his legs into a state, that allows him to easily run beside a truck speeding along the highway. While in the woods he morphs in lower legs into prongs that allow him to cling and jump through trees, becoming more agile than a monkey (stated by Migi).
His defense capabilities are far beyond that of a normal parasite. By having the parasites in each of his appendages harden themselves, he is able to fend of powerful shotgun blasts at close range, leaving only minor dents in his skin (holes in the anime). He has also created a shield using his forearm, by expanding and harding it. Though the shield was more of a demonstration, as he was left unscathed, from a direct hit from a grenade launcher.
Gotou has shown to be exceptionally dangerous in close quarters combat, by using his enhanced speed, he was able to kill dozens of armoured and weaponed soldiers in seconds.
Gotou is first seen leaving a vehicle, being driven by Kusano. He confronts a group of yakuza members, and proceeds to slaughter 21 of them. Before killing the last members he informs them he is testing his limitations. He leaves the area, only to be chased down by a few witnesses. After hiding himself, he picks off one of the men and changes his appearance, and returns to Kusano and drive off. They return to headquarters and tell Hirokawa of their success.
While Shinichi is waiting for Kana Kimishima in East Fukuyama City, Gotou is spotted. Gotou is standing next to Hirokawa, who is running for electoral office as a Mayor. He senses Migi in a group of spectators, and easily identifies him and Shinichi, though he shows no interest in them at the time. After Shinichi saves Shiro Kuramori in the parking incident, Hirokawa's group decide that Shinichi is interfering in their meal plan. While Reiko Tamura is inclined against this decision, she remarks that she wanted him alive and that he was a good subject. Gotou is appointed to retrieve Shinichi dead or alive, however unseen onscreen, Miki assumes control and chases Shinichi. After a confrontation in the woods, Gotou reassumes control and overwhelms Shinichi, almost killing him. He also reveals he is comprised of several parasytes. Shinichi is able to escape due to Gotou's blood loss.
During the military operation to eradicate parasytes in Hirokawa's hideout, Gotou shows his full potential. Slaying every soldier he encounters with little to no effort. He targets Shinichi next, assuming he is responsible for the preceding events, but he decides to leave Shinichi for another day. After these events Shinichi develops a severe persecutory delusion, causing him to believe he was being chased by Gotou. This indeed comes out as true, as both Migi and Shinichi are forced to face him. They come up with a fighting plan, but after their plan fails Migi is apparently killed. After Shinichi runs away and recuperates in a small village, Gotou begins killing several townspeople for sustenance.
For the last time Gotou is faced by Shinichi is his desperate revenge attempt. Gotou is stabbed in his weak point with a rusty metal rod, causing him to lose control over the other parasytes, which sense danger over toxins being injected into Gotou's body. Migi, who had been incorporated into Gotou's body, escapes his control and returns to Shinichi. Gotou, now exhausted, must coordinate his body and other parasytes, and force them to remain dormant in his body. He eventually fails and his body explodes, though he still manages to survive this ordeal. Because the explosion expelled the toxins from his body, he emits a signal to the other parasytes to regroup. Gotou still struggles to revive himself, while Shinichi begins to cry and apologize, as he eventually decides to kill Gotou.