This is a list of characters for the manga and anime series Parasyte and live-action Korean series Parasyte: The Grey.
Main characters
He is a high school teenage boy whose hand is infected with a Parasite and is repeatedly put into difficult positions. Shinichi 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 Migi's cells spread 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 Goto, with Migi deciding to "go to sleep" indefinitely afterward, Shinichi returns to Satomi and attempts to live a normal life again while having an understanding of natural order from his experience. 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 Monthly Afternoon magazine 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 issue of Monthly Afternoon.Iwaaki, Hitoshi (translated by Andrew Cunningham). Parasyte Volume 5. Del Rey Manga. P. 181 Shinichi is played by Shota Sometani in the film while Masaki Suda portrays Shinichi in the Korean series Parasyte: The Grey.
Migi is the Parasite which lives in Shinichi's right hand, named after the Japanese word for . 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 learning about the world), 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 Goto, having been absorbed by the Parasite prior to his defeat, Migi's composition is greatly altered to the point that enters a deep sleep, but not before expressing that he was glad to have met Shinichi and not having taken over his body when they first met. Migi briefly woke up to save Satomi from falling to her death 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. 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..."Iwaaki, Hitoshi (translated by Andrew Cunningham). Parasyte Volume 5. Del Rey Manga. P. 42 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.
Humans
Shinichi's best friend from high school, before Migi entered his life. She is a joyful yet perceptive teenage 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 into turmoil by the Parasites. Satomi does not know about Migi's existence, but senses something has happened to Shinichi who grows increasingly cold and withdrawn after the death of his mother. Despite her best efforts to find out the reason behind Shinichi's behavior, he refuses to share his secrets with her in order to shield her from Migi and the Parasite threat. Consequently Satomi becomes estranged from him as she increasingly resigns herself to the belief that the kind boy she fell in love with no longer exists. Ultimately, her faith in Shinichi is restored upon witnessing him weeping freely while protectively cradling Reiko Tamura's orphaned baby in his arms. At the end of the series, she was captured by the serial killer Uragami, who confronts her with Shinichi's secrets. Upon learning that Shinichi is part Parasite, Satomi firmly proclaims that this does nothing to diminish his humanity because he still regards all life as precious. In the manga, Satomi had a light brown short hair and was dressed in a sailor school uniforms, but in the anime, she has a changed appearance, especially a new maroon-colored hairstyle clipped up by a green hair clip that exposes her forehead, but no longer uses them in the last episode. Satomi is played by Ai Hashimoto in the film.
Kana is a disobedient "bad girl" who was seen hanging out with Mitsuo but develops a crush on Shinichi. She is attracted to him because of his sensitive personality because she can sense something "different" about him. In reality, Kana has the inexplicable psychic ability to sense other Parasites. 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 she comes face to face with a Parasite that kills her just before Shinichi came to save her. In the manga, Kana was depicted as a classic sukeban who does smoking, but she has a changed appearance in the anime where she was seen wearing a pair of earmuffs.
One of the students from Shinichi's school. Her brother works as a criminal profiling illustrator for the police department. Due to seeing his sketches of the Parasites and discovering Shimada's sinister secrets, she was caught in the center of a dangerous situation. Unlike her anime counterpart who got more screentime, Yuko's manga counterpart had no close relationships with Shinichi or Satomi and never had any feelings for Shimada.
A high school teenage girl who is usually seen hanging out with Murano and Yuko. Akiho only shows up in the anime and never appeared in the manga.
Like Akiho, he is another character who is one of Shinichi's classmates and only shows up in the anime,
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 Goto. 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 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 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 their 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.
One of Shinichi's classmates from his school. He had a crush on Murano and was jealous of Shinichi, so he ended up beating him up outside the gym. After Nagai was beaten by Mitsuo and his gang, Shinichi stood up for his classmate, so he changed his attitude towards him. In return, Nagai, along with his friends, attacked Mitsuo and his friends after they harassed Shinichi. In the anime, he also confronted Hideo Shimada if he has done something wrong to Shinichi. Unlike his anime counterpart, Nagai never had a crush on Murano or disliked Shinichi in the manga. In the scene after gym class, the person who attacked Shinichi was a minor character named Kotani who only shows up in the manga. Due to being omitted from the anime adaptation, his feelings for Murano and jealousy of Shinichi were transferred to Nagai.
A housekeeper hired by Shinichi's father. She never shows up in the anime, although Shinichi did suggest to his father if they can hire a housekeeper.
One of Shinichi's close friends from his school. In the manga, Kamijou was usually seen hanging out with Shinichi, often teasing him for his relationship with Satomi and went to his rescue when Shinichi was being attacked by Mitsuo and his group.
A student from Kana's school and also her boyfriend before Shinichi showed up. Mitsuo became jealous of Shinichi because of his girlfriend's crush on him. In the manga, he was depicted as a muscular teenage delinquent who is dressed in a school uniform. Mitsuo has a new appearance in the anime adaptation, portraying him as a young adult with a slimer body-figure, wearing a red jacket and a beanie on his head.
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 stay close to his father. It is shown that she develops a small crush on Shinichi during his stay in Sakurasaki.