Gotou

Gotou (後藤, lit. Gotō) is an 'experimental' parasite created by Reiko. His body is composed of five different parasites, whose power he can utilize to the fullest extent, making him one of the most powerful parasites in the story. He is the main antagonist of the series.

Appearance
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, four eyes and a mouth full of several rows of fangs. He also has four arms, a scythed tail, and digitigrade legs reminiscent of a dinosaur's.

Personality
Gotou is one of the more intelligent members 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 observing his enemies, and even allowing Shinichi to leave so that he may recover. Though he believes himself to be above humans, he still considers himself nothing other than a "wild organism" that "lives to fight".

Though he is arrogant and dismissive of humans, he is respectful enough of either Reiko or Hirokawa to stay under the human's control with the other parasites even when Reiko is suspected to be dead, only going solo during the city hall battle after Hirokawa chooses to give up. He is also willing to allow Miki to take over the body and hunt or fight despite Miki's lesser ability, stating he only needs more experience. Likewise, he willingly praises his opponents for decent strategy, though he finds being injured by a single human rage-inducing.

He displays some respect towards Reiko, contemplating her plans with Hirokawa and later acknowledging that she might have been a formidable opponent if they fought. Additionally, in the manga he is notably cordial with her, as he asks after her while she is on maternity leave and greets her when she returns from it.

In his transformed state, his thoughts become more primitive, focused solely on battle and survival. He was also more aggressive and became easily angered in this state, something that played a part in his downfall.

After being absorbed and escaping Gotou, Migi also reveals that due to the other parasites in his body having consumed heads as well, he feels five times the bloodlust and desire to kill humans that a normal parasite would, making him a perfect "killing machine".

Plot
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 outfit and 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, Migi senses multiple parasites and goes to investigate. They eventually determine that there are 6 parasites on a podium and spot Gotou. He 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 Kana's death, he is seen in a meeting with multiple other parasites discussing the incident. He points out that because of this, the human authorities have recovered another parasite specimen to examine. However because the parasite in question had not been following with their plans, they decide to follow Reiko's request to leave Shinichi to her.

After Shinichi saves Shirou Kuramori in the parking incident, Hirokawa's group decide that Shinichi has become too big of a threat, having killed one of them in their "dining rooms". While Reiko Tamura is inclined against this decision, she remarks that she wanted him alive and that he was a good subject. Gotou is suggested to retrieve Shinichi dead or alive, but he declines and allows Miki to assume control offscreen, who chases Shinichi. After a confrontation in the woods wherein Miki fails, Gotou reassumes control and overwhelms Shinichi, almost killing him. He incidentally reveals he is comprised of five parasites. Shinichi is able to escape due to Gotou's blood loss.

During the military operation to eradicate parasites in Hirokawa's hideout, Gotou shows his full potential, slaying every soldier he encounters with little to no effort and only being slightly wounded. 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 townspeople for sustenance.

For the last time Gotou is faced by Shinichi in his desperate revenge attempt. Gotou is stabbed in his weak point with a rusty metal rod, causing him to lose control over the other parasites, 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 internally wounded due to Migi's efforts before his escape, must coordinate his body and other parasites, and force them to remain dormant in his body. Distracted, he charges in a rage at Shinichi and does not defend in time from being decapitated. Because of the internal struggle between parasites his body explodes, though he still manages to survive this ordeal as his host body's organs are still intact. The explosion expelled the toxins from his body, so he emits a signal to the other parasites to regroup. Gotou struggles to revive himself, while Shinichi begins to cry and apologize, as he eventually decides to kill Gotou and finally destroys Gotou, the other parasites and their host body.

Abilities & Powers
As a parasite, Gotou has the basic abilities to shapeshift his head, and maximize the physical potential of the body he is controlling. However, as his body is composed of four other parasites, each replacing a different limb, these parasite abilities extend to all of his body. This makes him far faster, stronger, and more dangerous than standard parasites, and nearly impossible to injure.

Gotou is the most intelligent and skilled, and is the de facto leader of the composite body. Under his control, their combined offensive, defensive and movement capabilities are far beyond that of normal parasites. He is capable of hardening them into highly durable body armor that can withstand a direct grenade blast with only superficial damage and fend off military-grade shotgun blasts at close range, leaving only quickly-repairing holes.

He is able to alter the parasites in his legs to adapt to multiple situations, greatly increasing his mobility. These include bladed prongs that allowed him to cling and jump through trees with high speed, accuracy and agility, long digitigrade legs capable of running upwards of 60 km/h (~37 mph), and modified feet and calves that allow him to rapidly rebound off walls and ceilings.

His arms can similarly be modified. For battle they are usually transformed into varieties of the common bladed tentacles, but he has also used them as channels to gather bullets shot into him and sling them back at lethal speed, and a shield made from an expanded and hardened forearm to deflect further bullets. Even when untransformed his arms are capable of incredibly high force. Gotou has shown to be exceptionally dangerous in close quarters combat. By using his enhanced speed and transformed body, he was able to tear apart dozens of armored and heavily armed soldiers in seconds and only sustained minor damage.

When in the wild he chooses to change into a secondary form, a monster 3 meters (~10 feet) tall with multiple extra eyes, limbs, and teeth. He also reveals the capability to absorb more parasites as he absorbed Migi into his body for a small period of time and would have been able to keep Migi there if he had not been poisoned. Thus, his upper capacity for total number of parasites he can control remains unknown.

Weaknesses
Because Gotou's body armor is made of rigid parasite cells, he needs to allow several small unarmored spots to be able to move. One of them is on his lower left side. Albeit small, it was still large enough to allow two shotgun pellets to penetrate him, causing him to bleed. Another is in his neck, leaving him able to be decapitated or stabbed through his esophagus if he is unable to defend. When sleeping or otherwise stationary, he can armor up completely to negate this weakness.

Like all other parasites his human host organs remain his main vulnerability, and he would be killed if they were destroyed. Another weakness he shares with regular parasites is his inability to tolerate fire, causing his cells to panic and temporarily leave his control. This can unbalance him and leave him off guard.

He is unable to shapeshift his head to be used in battle as all his focus is on controlling and coordinating the other four parasites. Because of this, decapitation is a good strategy against him to temporarily cause confusion and stop the other parts of the combined parasite form from attacking. Additionally, if the parasites inside him aren't fully under his control, they can rebel against him, damaging him or causing his body to become weakened and potentially explode. Due to being incorporated in Gotou's body, Migi was able to damage Gotou's organs on the way out.

His arrogance towards humans proved to be a weakness as well, causing him to be wounded slightly during the city hall battle and in Shinichi's final confrontation with him when he likely could have killed Shinichi in mere seconds.

He has also shown to still be susceptible to poisons, causing great confusion in his body as the parasites sharing it detect the poison, wake up and attempt to escape.

Trivia

 * The name Gotou means "behind, later" (後) (go) and "wisteria" (藤) (tō).
 * This name is also a pun as one of the kanji is homophonous with the kanji for five (五) (go), implying he can control 5 Parasites, whereas the other Parasite in the same body called Miki (三木, lit. Three trees) can control only 3; Miki also has an additional meaning, being similar to "Migī".
 * His name in some translations was only "Goto" or "Gotoh", but that later was fixed as the manga was being republished again. With the anime adaptation, his name in English is confirmed "Gotou".
 * His official job may be as Hirokawa's bodyguard or assistant, as he is often seen in Hirokawa's company.
 * In the anime Gotou is shown playing Chopin's Nocturne Op. 9 No. 2. In contrast, the manga displays bars of Chopin's Étude Op. 25, No. 11 as he's playing.
 * Hitoshi Iwaaki originally had two different fates planned out for Gotou:
 * Gotou completely revived himself, but due to hating Japan's polluted air, grows a pair of wings and flies to a more beautiful location.
 * Gotou partially revives, but turns into a different creature entirely, preying on humans.
 * Hitoshi believed that both of these were awful and rather lazy, thus decided against them.
 * Gotou appears in the Parasyte Reversi spinoff.