This is a list of characters for the manga and anime series Parasyte and live-action korean series Parasyte: The Grey.

Shinichi Izumi (泉 新一, Izumi Shin'ichi)

Voiced by: Nobunaga Shimazaki^[1] (Japanese); Adam Gibbs^[2] (English)

Shinichi is a thoughtful, compassionate high-school boy whose hand is infected with a Parasite and is repeatedly put into difficult positions. He must find a way to peacefully coexist with Migi, the Parasite which has taken over his hand, and reconcile his desire to protect humanity from the Parasites with his desire to keep his own Parasite a secret in order to avoid being killed or used as a laboratory specimen. Like a superhero with a secret identity, he must also find a way to explain away his Parasite-fighting activities, as well as the stress and grief they cause him, to his friends and family. While originally forced to have Migi fight for him, Shinichi later gains heightened abilities when trace cells of the Parasite course through his body, and fights his own battles, with the two having an advantage in both being able to act independently and work as a team. Shinichi's retention of his humanity, despite gradually becoming emotionally distant as a side-effect of Migi's cells, makes most of the other Parasites deem him a threat. After defeating Gotou, with Migi deciding to "go to sleep" indefinitely afterward, Shinichi attempts to live a normal life again while having an understanding of natural order from his experience, and starts dating Murano.

Sometime later, Shinichi goes to South Korea and offers to help Jun-Kyung and Team Grey get rid of the parasites.

Masanori Harada, a 20-year-old student, wrote to the editor of the Monthly Afternoon noting that Shinichi acts calm when he is threatened and that he is "not human anymore!" Iwaaki responded, stating that Shinichi is accustomed to "close calls" partly because Migi calms Shinichi down during battle. The statement and response were printed in the April 1993 Monthly Afternoon.^[3]

Shinichi is portrayed by Shota Sometani in the film while Masaki Suda portrays Shinichi in the Korean series Parasyte: The Grey.

Migi (ミギー, Migī, also called "Righty")

Voiced by: Aya Hirano (voice),^[1] Rinka^[4] (sound effect) (Japanese); Brittney Karbowski^[2] (English)

Migi is the Parasite which lives in Shinichi's right hand, named after the Japanese word for "right" (右, migi). Unlike "successful" Parasites, Migi has no desire to kill humans for sustenance, and is nourished by the food Shinichi eats, however he suffers from fatigue and regularly falls asleep for four hours at a time, leaving Shinichi vulnerable. Migi is, like other Parasites, completely without emotion. His primary consideration is survival, and he has threatened (and in some cases attempted) to kill other humans who pose a threat to his and Shinichi's secrecy. When he and Shinichi were first coming to terms, he even threatened to remove Shinichi's other limbs in order to render him unable to place the two of them in danger. Migi can be reasoned with, however, and has just as much reason to be mistrustful of other Parasites as does Shinichi. On the other hand, unlike Shinichi, Migi has no inclination to place himself at risk in order to protect other humans from Parasites. But Migi gradually evolves over the course of the series, he becomes more human while able to temporarily separate from Shinichi's body. After the final battle with Gotou, having been absorbed by the Parasite prior to his defeat, Migi's composition is greatly altered to the point that enters a deep sleep though he briefly woke up to save Satomi without Shinichi's realization.

Iwaaki explained that while Migi appears to be Shinichi's weapon, in fact Migi is in control of the battle and orders around Shinichi. Iwaaki explained that Migi is easily able to order Shinichi since Shinichi is young and "needs guidance", while Migi would find difficulty if he became a part of a politician or a president of a company since in that scenario Migi and his host would argue a lot.^[3]

An 18-year-old from Saitama Prefecture named "Midari" asked in the letters to the editor that if Migi took Shinichi's left hand, if he would have been named "Hidari". Iwaaki answered that it would be Hidari, but Iwaaki felt that the name would be similar to those of Bokuzen Hidari or Tenpei Hidari and the name would "bring to mind a doddering old man, so that wouldn't have been a good idea". Iwaaki then said that the first man to climb Mount Everest "had a name an awful lot like that..."^[5]

Migi is voiced by Sadao Abe in the film.

Jeong Su-in / Heidi (정수인)

Portrayed by: Jeon So-nee

a parasite victim with a traumatic past and when it fails to take over her brain, she enters a bizarre coexistence with it, unlike other parasites.^[6]

Satomi Murano (村野 里美, Murano Satomi)

Voiced by: Kana Hanazawa^[1] (Japanese); Luci Christian^[2] (English)

Shinichi's best friend and love interest. She is a thoughtful, tender-hearted young girl who cares deeply for her friends. While Satomi and Shinichi are mutually attracted towards one another, their relationship is strained to the breaking point when Shinichi’s life is thrown in turmoil by the Parasites.

From the moment she is introduced, Satomi is depicted as being romantically attracted towards Shinichi due to his kind and sensitive nature. Consequently, she becomes grief-stricken as she watches him grow ever more cold and withdrawn over the course of the story. Despite her best efforts to find out the reason behind Shinichi’s behavior, Satomi becomes increasingly estranged from him as he desperately strives to keep her in the dark about Migi and the Parasite threat. As a result, she begins to question whether any trace of the gentle, caring boy she originally fell in love with remains. After nearly losing all hope, Satomi’s faith in Shinichi is restored upon witnessing him crying freely while protectively cradling Reiko’s orphaned baby in his arms. Upon learning that Shinichi is part Parasite, Satomi firmly proclaims this does nothing to diminish his humanity because he still regards all life as precious. At the series' conclusion, the two are revealed to have ended up together as a couple.

Satomi is played by Ai Hashimoto in the film.

Kana Kimishima (君嶋 加奈, Kimishima Kana)

Voiced by: Miyuki Sawashiro^[7] (Japanese); Maggie Flecknoe (English)

Kana is a disobedient "bad girl" who initially hangs out with Mitsuo but develops a crush on Shinichi. She is attracted to him because of his sensitive personality, and because she can sense something "different" about him. In reality, Kana has the inexplicable psychic ability to sense parasytes. However, her senses are not as fine tuned as those of the Parasite themselves. Kana mistakes this sense as a psychic connection to Shinichi, believing it was fate leading her to her true love. This ability eventually leads to her death when she is told about the Parasite, but stubbornly refuses to believe the truth until, thanks to her ability, she comes face to face with a parasyte that kills her just before Shinichi came to save her. Her death brings a total breakdown of Shinichi for some time.

Yuko Tachikawa (立川 裕子, Tachikawa Yūko)

Voiced by: Kiyono Yasuno^[7] (Japanese); Terri Doty^[2] (English)

One of Satomi's two best friends. Her brother works as a criminal profiling illustrator for the police department. Due to her seeing her brother's sketches of Parasites and her crush on Hideo Shimada, she ended up at the center of a highly dangerous situation.

Akiho Suzuki (鈴木 アキホ, Suzuki Akiho)

Voiced by: Rena Maeda^[7] (Japanese); Hilary Haag (English)

The other of Satomi's two best friends, who has a minor crush on Shinichi.

Uragami (浦上)

Voiced by: Hiroyuki Yoshino^[7] (Japanese); Andrew Love^[2] (English)

A cannibalistic serial killer who has the ability to distinguish between humans and Parasites, believing himself to be the definition of human nature and able to point out a killer. He is brought in by the military to help them in their operation to exterminate the Parasites in East Fukuyama City, but escapes when the military unit is slaughtered by Gotou. He returns at the end of the series, taking Satomi hostage to confront Shinichi to see if he has the same world views as he does.

Uragami is played by Hirofumi Arai in the film.

Kazuyuki Izumi (泉 一之, Izumi Kazuyuki)

Voiced by: Masaki Aizawa (Japanese); Rob Mungle^[2] (English)

Kazuyuki is Shinichi's father. Shortly after his wife was killed by a Parasite, he had some suspicions as to whether or not Shinichi was infected (although he never said so outright).

Nobuko Izumi (泉 信子, Izumi Nobuko)

Voiced by: Chieko Sasai (Japanese); Allison Sumrall^[2] (English)

Nobuko is Shinichi's mother, expressing concern over her son's strange behavior. She dies early on when she is decapitated by a Parasite that needed a compatible body to transfer to when her male replacement body started to reject her. As the Parasite assumed Nobuko's appearance, Shinichi let himself open and got himself nearly killed in the initial encounter. But Shinichi later manages to avenge his mother's death and kills the Parasite with Uda's help.

Nobuko is played by Kimiko Yo in the film.

Kazuki Nagai (長井 和輝, Nagai Kazuki)

Voiced by: Shinya Hamazoe (Japanese); Houston Hayes (English)

One of Shinichi's classmates at high school. He had a crush on Murano and therefore was jealous of Shinichi, beating him up outside the gym in the anime. After Shinichi intervened while he was being jumped by Mitsuo's gang, he's changed his demeanor. Nagai is quick to jump into situations as seen when he got in Shimada's face for confronting Shinichi. The scene where Nagai assaults Shinichi after gym class, originally involved a character called Kotani. Due to Kotani being omitted from the Parasyte -the maxim- anime series, the scene was transferred to Nagai.

Mitsuo (光夫)

Voiced by: KENN^[8] (Japanese); Scott Gibbs (English)

A student from Kana's school and possibly her ex-boyfriend, he is jealous about his ex-girlfriend's (Kana) crush which is Shinichi.

Makiko Hayase (早瀬 真樹子, Hayase Makiko)

Voiced by: Yu Serizawa^[8] (Japanese); Margaret McDonald (English)

Makiko is a young schoolgirl who lives with her parents, grandfather, and younger brother in the small town where Shinichi's father is hospitalized. Her family owns a hotel in the town where Shinichi stays for a few days, in order to be near his father. It is shown in the series that she develops a crush on Shinichi during his stay.

Mamoru Uda (宇田 守, Uda Mamoru)

Voiced by: Takuma Suzuki^[8] (Japanese); Mark X. Laskowski (English)

Uda is, like Shinichi, a human who had a Parasite merged with a part of his body other than his brain. In Uda's case, the Parasite took over the lower part of his head and face, most notably his jaw. Uda's Parasite originally does not have a name, but is later renamed Joe (ジョー, Jō, after the English word "jaw") (Voiced by: Ayumu Murase (Japanese); Greg Ayres (English)). It is brash and crude, seemingly having a sense of humor, and often assumes control of Uda's mouth, distorting it into odd shapes and forcing Uda to say strange or inappropriate things. The pair befriend Shinichi and Migi, but preferring to simply avoid Parasites. Because Uda is slightly overweight and his Parasite is located in the jaw area, fights with other Parasites tend to leave him out of breath. However, because it is located in the lower part of the head, his Parasite can extend itself downward into his chest, protecting his heart (a primary target for hostile Parasites). Uda is a peaceful, easygoing man, but is shown to be nervous under pressure and highly emotional, often crying easily. He works as a hotel employee.

Shiro Kuramori (倉森 志郎, Kuramori Shirō)

Voiced by: Issei Futamata (Japanese); Jay Hickman (English)

A private investigator hired by Reiko to spy on Shinichi and caught by Migi when he takes picture of them. When his assistant Abe goes missing, Shiro asks Shinichi to find him, and ends up recording a fight between Shinichi and a Parasite. Later his family is killed by Parasites, and in a frenzy of grief he kidnaps Reiko's infant son, leading to a critical confrontation at a park.

Takeshi Hirokawa (広川 剛志, Hirokawa Takeshi)

Voiced by: Yū Mizushima^[8] (Japanese); John Gremillion (English)

The ringleader of a Parasite conspiracy to conquer humanity and the main antagonist of the latter half of the series. In order to realize his vision of culling the human race for the planet's well-being, he lends his resources and political acumen to unite the Parasites and transform the chaotic "Mincemeat Murders" into a streamlined process of mass slaughter. Aside from his professed environmentalism and his deep-rooted hatred of humanity, nothing is revealed about his character or background.

Mid-way through the series, Hirokawa is elected mayor of East Fukuyama City, a municipality near Shinichi's hometown. Subsequently, he uses his authority to set up safehouses where the Parasites can kill and eat humans with impunity. After Shinichi and Migi disrupt the operation of one of these facilities, Hirokawa targets them for elimination. Eventually, he and most of the Parasites comprising his organization are killed by a police task force once their plans are uncovered by the authorities.

Hirama (平間)

Voiced by: Takuma Suzuki (Japanese); George Manley (English)

A veteran detective who first suspected Shinichi for Kana's death.

Yamagishi (山岸)

Voiced by: Rikiya Koyama (Japanese); Josh Morrison (English)

A police officer assigned to the Parasyte Extermination Squad, who is eventually beheaded by Gotou.

Mitsuyo (美津代)

Voiced by: Seiko Fujiki (Japanese); Vicki Barosh (English)

An old woman who gave shelter to Shinichi after his fight with Gotou in the forest. After staying for a while, he left to have the final confrontation with Gotou.

Seol Kang-woo (설강우)

Portrayed by: Koo Kyo-hwan

A small-time gangster who initially tracks down parasites in order to find his younger sister, Jin-hee, but ends up teaming with Su-in.^[6]

Choi Jun-kyung (최준경)

Portrayed by: Lee Jung-hyun

The team leader of "Grey Team", a task force that wants to eradicate parasites.^[6]

Kim Cheol-min (김철민)

Portrayed by: Kwon Hae-hyo

A senior detective at Namil Police Station, whom eventually becomes infected with a parasite.^[9]

Kang Won-seok (강원석)

Portrayed by: Kim In-kwon

Cheol-min's junior detective who also secretly teamed up with the parasites.^[9]

Seol Jin-hee

Portrayed by: Moon Ju-yeon

Kang-woo's younger sister who went missing.

The antagonists of the series. The Parasites are creatures of unknown origin which start off as worm-like creatures that instinctively enter the body of the nearest life form and travel to the brain to completely assimilate it while destroying the host's identity in the process. From there, using the vital organs of the host bodies to survive, the Parasites would be driven with a need to kill humans and Parasites with failed host bodies. After assimilating their host, Parasites exhibit a variety of abilities that make them dangerous adversaries: the immediate area around their entry site (typically the head) is morphed into a versatile "parasite tissue" which can take a variety of offensive and defensive forms, and a parasite that successfully takes over a host's brain can then maximize the physical potential of that host. In general, Parasite intelligence is comparable to humans, though their thought process is strictly rational and cold, with very little emotion. They are also capable of learning extremely quickly depending on their environment – Migi, for example, mastered Japanese after one night of reading books on the subject. While most Parasites initially acted alone, causing a chain of multiple grisly deaths coined the "mincemeat murders", they eventually form groups for safety in numbers. By the time of the final chapter, Shinichi speculating that they might have been created as an evolutionary countermeasure to humans, the surviving Parasites are assumed to have gone into hiding and adopt themselves further into human society to keep their activities to a minimum.

Reiko Tamura (田村 玲子, Tamura Reiko)

Voiced by: Atsuko Tanaka^[7] (Japanese); Joanne Bonasso (English)

An extremely intelligent, ruthless Parasite and the main antagonist of the story's first half. She originally infected and took on the identity of a woman named Ryōko Tamiya (田宮 良子, Tamiya Ryōko), one of Shinichi's high school teachers. Unlike most of her kind, she is motivated by scientific inclinations with a drive to understand her kind's biology, origin, and purpose. In her quest for knowledge, she goes so far as to become pregnant with a normal human infant for the purpose of studying it.

Upon encountering Shinichi and Migi, Ryoko becomes obsessed with learned about their unique symbiotic relationship. In the process of satisfying her intellectual curiosity, she knowingly endangers the lives of Shinichi and his loved ones by exposing them to violent Parasites such as Mr. A and Hideo Shimada. In the latter half of the series, she adopts the identity of "Reiko Tamura" and aligns herself with Takeshi Hirokawa in a conspiracy to conquer humanity. However, after giving birth to a human baby, Reiko finds herself developing feelings for it and begins harboring reservations about Takeshi's plans. When other Parasites involved in the organization observe this sudden change in her behavior, they grow suspicious of Reiko and attempt to kill her. Reiko subsequently kills all of them and abandons Takeshi's organization. In her final encounter with Shinichi, Reiko informs him she has come to the realization that Parasites can coexist with humans if permitted to live among them. When police arrive on the scene and open fire on her, she serenely accepts her fate before entrusting Shinichi with her child's safety.

Tamura is portrayed by Eri Fukatsu in the film.

Mr. B (B)

Voiced by: Tōru Nara (Japanese); Mike Yager (English)

A Parasite who attacks Shinichi and tries to coerce Migi into relocating to his arm in order to extend his own lifespan. To his surprise, Migi kills him on the pretense that relocation is too risky to try.

Mr. A (A, Ē)

Voiced by: Makoto Yasumura (Japanese); David Wald (English)

A highly aggressive Parasite aligned with Reiko Tamura. When first introduced, he (or rather, his host body) fathers a child with Reiko as part of the latter's experiment. Described by Migi as "not one of our smart ones" and called a fool by Reiko, Mr. A is extremely impulsive and animalistic. He has little capacity for caution or forethought as evidenced when he butchers several people in the presence of witnesses without hesitation. Shinichi is forced to battle Mr. A when he attempts to hunt Shinichi down and kill him at school. Though Shinichi and Migi mortally wound him, they are forced to flee before they can kill him. Mr. A attempts to find Reiko to transfer himself to her body and survive, but she rigs the room to explode to completely destroy him to preserve her human cover.

Hideo Shimada (島田 秀雄, Shimada Hideo)

Voiced by: Akira Ishida^[8] (Japanese); Blake Shepard (English)

A Parasite with the body of a young adult and a major antagonist. On Reiko's suggestion, Hideo enrolls in Shinichi's high school to monitor his activities. Despite being one of the more pragmatic of his species, he has no qualms feeding on humans or otherwise killing them if they annoy or threaten to expose him. Ultimately, his single-minded desire to preserve his cover at any cost lead him to become a direct threat to Shinichi's loved ones.

When first introduced, Hideo Shimada is asked by Reiko to monitor Shinichi in order to confirm he poses no threat to their kind. Subsequently, Hideo enrolls in Shinichi's high school and expresses a desire to become friends with Shinichi, who does not trust him. Despite professing a willingness to peacefully coexist with humanity, he nearly kills a group of bullies who try to start fights with him, and continues to prey on humans. When Yuko uncovered his secret and confronts him about it, Hideo attempts to kill her only for Yuko to escape by dousing him in paint-thinner. The paint-thinner's chemical make-up disrupts Hideo's Parasite cells, causing him to go on an involuntary killing spree across the school. He is killed after he escapes to the roof, when Shinichi, using Migi to enhance his right arm's strength, throws a well-aimed stone through his chest, destroying his heart.

Shimada is played by Masahiro Higashide in the film, where Shinichi and Migi kills him not by throwing a stone, but piercing his chest with an arrow-like bar shot thanks to Migi, who uses his body to create a bow.

Gotou (後藤, Gotō)

Voiced by: Kazuhiko Inoue (Japanese); Jason Douglas (English)

The strongest Parasite and a major antagonist in the series. His host body contains 4 additional Parasites that are completely under his control. Since most of his body mass is parasite tissue, he can achieve feats of strength and agility far in excess of normal parasites and render nearly every inch of his skin impervious to gunfire and edged weapons. Despite being one of the more intelligent of his kind, Gotou is also one of the most violent. Whereas most Parasites kill humans to feed or eliminate threats, he often hunts them sheerly for sport. Nonetheless, Gotou does possess his own peculiar code of honor as seen when he commends opponents for getting past his defenses and seeks vengeance against Shinichi for his role in his comrades’ massacre at East Fukuyama City Hall. The name "Gotō" is a pun as one of the kanji is synonymous with the kanji for five (五, go), a reference to how 5 Parasites inhabit his host.^[10]

Gotou is introduced as the chief enforcer and right-hand man of Takeshi Hirokawa, the leader of a Parasite conspiracy to conquer humanity. After Shinichi and Migi attack one of his organization’s "dining areas", Gotou is tasked with eliminating them. Despite easily overwhelming the two in combat, they narrowly manage to escape. Later, when Hirokawa and his group are killed in an SAT operation, Gotou singlehandedly wipes out most of the attacking police forces before once again targeting Shinichi and Migi. During their rematch, Gotou absorbs Migi after the latter sacrifices himself so Shinichi can retreat. During the story’s climax, Shinichi poisons him by stabbing one of his few vulnerable areas with a pipe contaminated with toxins. As a result, Gotou loses control of the other Parasites in his body thereby enabling Migi to break free and help Shinichi finally defeat him.

Miki (三木, lit. Three trees)

Voiced by: Daisuke Namikawa (Japanese); Xero Reynolds (English)

One of the Parasites that composes Gotou's body. Similar to "Migi", Miki's default position in the body is the right arm. His name has an additional meaning, which means "Three trees", referencing how he is only able to manipulate 3 Parasites in the body (including himself) when he takes the head position. Unlike other Parasites, Miki has learned to show emotions just like humans.^[10] His body is composed of five Parasites, one in each of his arms and legs and another in his head, they can apparently swap their places in the body but only two of them are able to unify the five and make them fight as a single being.

Kusano (草野)

Voiced by: Takaya Aoyagi (Japanese); Kalob Martinez (English)

A Parasite that allied himself with Reiko Tamura along with two others named "Hikawa" and "Maesawa." He later grows distrustful of Reiko Tamura when she argues against the notion of killing Shinichi despite the threat he poses to them. As Kusano's doubts about Reiko increase, he attempts to assassinate her with help from Maesawa and Hikawa. But his underestimation of Reiko's abilities results in the death of himself and his conspirators.

Seol Kyung-hee

Portrayed by: Yoon Hyun-gil

Kang-woo's elder sister who is infected by a parasite.

Kwon Hyuk-joo

Portrayed by: Lee Hyun-kyun

A pastor, and the leader of the parasites in South Korea.

In the Tokyopop publication the main character's name was Shin and his hand was called "Lefty", as the image had been flipped to read left to right.^[11] Satomi Murano is Sara. Jaw, Uda's Parasite, is referred to as Jaws, in reference to the film Jaws by Steven Spielberg. Reiko is known as Tamara Rockford in the Tokyopop version.^[12] Gotō's name was written without a macron.