Hizuru Minakata (南方 ひづる, Minakata Hizuru) is a mysterious woman, who visits the island for the first time in 14 years for a certain reason. She is also known as Ryunosuke Nagumo, author of the novel "Swampman". She has a dual personality and her brother Ryunosuke Minakata takes over when she is forced to do things she dislikes.
Hizuru is an adult woman with long black hair and violet eyes with a large bust. She has a mole on the left side of her mouth. Hizuru tall woman wearing a suit and glasses.
Hizuru heads for Hitogashima and on the boat, Shinpei bumps into her and she slaps him. The next day Shinpei visits the shrine to get an exorcism. He goes into the woods and finds Hizuru bleeding. As she tries to warn him, shadow Mio appears and shoots her in the head.
The second time Shinpei awakens on the boat, Hizuru asks him if he is okay, as he seemingly had a nightmare. He asks her if she was ever shot with a handgun, but that causes Hizuru to even more wonder if he is okay.
On the third time, a bit more than a hour after arriving on Hitogashima, Hizuru hands upside down from a tree and records herself, explaining that she ate and that she is hanging upside down to think better. She then observes Shiori, commenting that its walking free among the people and plans on keep watching for the moment.
At the summer festival, little before the ceremony, Hizuru finds shadow Mio trying to break Shinpei's leg on the stairs towards the shrine, and blows Mio's head with her shotgun. Mio retreats in her shadow and slides towards Hizuru, attempting to stab her from behind, but Hizuru dodges and shoots her shadow, which kills Mio. Hizuru then introduces herself as Ryunosuke Nagumo and explains she came to save Shinpei Ajiro. Seeing a shadow, Hizuru then hides with Shinpei and they see Ushio running up the hill, but Hizuru tells him to not go as the shadows are gathering there. Hizuru explains that shadow's true forms are their flat shadows on the ground and they don't like being stepped on. They eat by eating human data, but for the sense of taste, they need to consume the human, which leaves black stains. She has been killings many shadows since she came on the island, but their numbers keep increasing fast. Seeing a flash on the hill, Shinpei asks Hizuru for help and they head uphill.
There, they witness a massacre and a big pile of corpses. Hizuru shoots Shadow Sou's hands and saves Mio from him. However, a shadow then produces another from itself which points a gun at Hizuru, making her realize its the parent shadow. Seeing a glimpse of the future, Hizuru sees she is shot in the head and dodges in the last moment and gets shot in the arm. The parent shadow then starts consuming the humans, offering them to their Mother, who then appears in the sky and Hizuru recognizes her as Heine. As everyone on the island starts to be consumed, Hizuru apologizes to Shinpei, stating she should have believed the message earlier. Shinpei tells her its not too late and asks her to shoot him in the head as he will return in time back to 22nd. Hizuru believes him and tells him that if he returns, to find her and tell her his name is Shinpei Ajiro. Hizuru then shoots Shinpei and gets consumed by the shadow.
On the fourth time, upon stepping on Hitogashima, Hizuru notices a man's shadow avoiding her foot. She overhears Mio calling Shinpei "Shin" and considers he may be Shinpei Ajiro. She notices a message about Ushio Kofune's funeral and recognizing the name she goes to the funeral. There she meets Masahito Karikiri, who recognizes her, but quickly recalls why she couldn't stand him. She meets Alain Kofune and recalls how she used to spend time in the Kofune restaurant. She overhears Alain that Shinpei and Mio will be late and questions Alain about Shinpei. Realizing its Shinpei Ajiro, she decides to leave and avoid meeting him for now. Alain follows her and tells her that Ushio had marks on her neck similar to strangling and feels her death sounds similar to Ryunosuke Nogumo's. Hizuru returns to check the mark on Ushio's neck. As she leaves, he asks Alain if Ushio mentioned she met a doppleganger, but he didn't knew. Asako, an old friend of Hiruzu, recognizes her and explains that Ushio saved her daughter Shiori Kobayakawa, however, Hizuru notices that Asako's shadow is avoiding her foot and that the whole Kobayakawa family are shadows.
Hizuru meets with Ginjiro and tells him about the Kobayakawas. As the shadows number increases, Ginjiro states there is one that can generate new shadows. Hizuru speculates that Shiori was being drowned by Shadow Shiori, and then erased Shiori and acted as she was the one being drowned, and later killed the rest of the Kobayakawas. Hizuru gives her second phone to Ginjiro and tells her to tell him if it rings. At the crematorium, she follows Alain in the bathroom and puts a "maintenance" on his toilet stall. A Shadow Alain comes and opens a stall, but finds Hizuru, who then smashes his shadow on the ground with a hammer and kills it. She receives a call from Ginjiro that Shinpei contacted him after solving her code and goes to meet him at the fourth battery. There Ginjiro explains that to solve Hizuru's code, you must know that Hizuru and Ryunosuke are the same person, which is something that only he knows or if a shadow copied Hizuru. Meeting Hizuru, Shinpei reveals his name is Shinpei Ajiro and wants an autograph from Hizuru. Hizuru tells him to correct her if she says something false. She then explains that he didn't knew who she was while on the boat and the only way a human to know her real name is if she had revealed it. Hizuru notes that this isn't the first time he experienced July 22nd and repeated in multiple times. This would mean, he is a time traveler. Shinpei starts crying and confirms.
Shinpei reveals his notes about the Shadows and Hizuru believes him as her family was also killed by a shadow. He asks her to help him kill Mio's shadow and Hizuru agrees to help, but first needs to deal with Kobayakawas. Shinpei reveals he saw Shiori at the festival, so she must have escaped Hizuru. They go to the Kobayakawa's house, where Hizuru turns into Ryunosuke, her brother. He rings on the door and gets in as Hizuru knows Asako from childhood. Once inside, he opens his back and takes out a hammer and immediately attacks Asako, smashing her head. Tatsuo, Asako's husband, attacks him, but he smashes his head as well. Asako stands up and attempts to attacking him, but seeing a glimpse of his death, Ryunosuke avoids and kills Asako's shadow. Shiori then appears behind him and as he turns, he smashes her shadow, but Shiori still lives and moves away. She then attacks Ryunosuke and starts choking him, stating he is dangerous as he knows how to kill shadows and wonders if he is even human as he moves really fast. Ryunosuke suggest that she scan him and learn herself, but then grabs chopsticks and stabs himself as Shiori's shadow is on his body. Shiori survives and runs on the third floor. Ryunosuke text Ginjiro and Shinpei that Asako and Tetsuo are dead, but Shinpei may be right for Shiori escaping and they should move to Plan B. He goes into her room and texts that she escaped from the window. Shiori then appears behind him, but Ryunosuke states its pointless as if she attempts to scan him, he knows that she will be unable to move for couple of seconds and will kill her. Annoyed, Shiori retreats in her shadow and runs thought the window. Ginjiro attacks her with a nail gun, but misses. Shinpei tackles her and manages to get her and Ginjiro then pins her with three nails, explaining that if pierced three times, the shadows can't move. As Ryunosuke comes, he comments they learned something new that the 3D body can't retreat into the shadow once they are pinned. He asks Shiori if she killed Ushio and Shiori confirms. Shinpei gets angry and asks about their goal, but Shiori states the end is coming and she was trying to leave with her family. She proceeds to explain that she is reborn and is now the real Shiori, but Ryunosuke kills her, stating that if you talk too long with a shadow you will be misled. Ryunosuke introduces himself to Shinpei as Ryunosuke Minakata, Hizuru's brother. He explains he takes over when Hizuru is forced to do things she dislike, like interviews. He guesses that Shinpei had read Hizuru's novels, but Ginjiro reveals he is actually a freaky fan. Ryunosuke is surprised as Hizuru notes didn't mention that, but in that moment, he punches himself and Hizuru takes over, stating they are going off topic. The group exchanges phones and Hizuru tells Shinpei to continue acting as he would, and be their observer until shadow Mio arrives.
About 10 minutes before shadow Mio appears, Ginjiro tells Ryunosuke to not take everything that Shinpei told them as prey can be unpredictable. Soon, Shinpei opens the curtains, making them realize that Mio is there. Ginjiro shoots Mio and Shinpei kills her. Ryunosuke then enters his room and prepares to kill shadow Ushio, but Shinpei protects her, asking Hizuru to help her and explains that she saved him two times. Realizing her voice is the same as the message she got, Hizuru agrees. Outside, she pours water on her arm and Ushio's arm disappears. She explains that the wound was a projection of the damage done to her main body. Hizuru shows her the message, where Ushio asks her for help and explains that she shadows kill everyone at the festival and only Shinpei Ajiro can stop them, however, Ushio has no memories of it. They realize that somehow the shadows knew they killed Shiori, but Hizuru decides to stop working with Shinpei due to him sticking with Ushio. While she means no harm right now, they don't know when she will be "fixed" and turn against them. Before leaving, Shinpei tells her that Hizuru was killed by Mio on the next day at 3PM in the forest near the shrine and to be careful as a replacement may be send.
Having a bad feeling about the sewers, Hizuru turns into Ryunosuke and along with Ginjiro they go underground. They encounter and kill some baby-like shadows. Ryunosuke and Ginjiro reach a dead end with metal bars blocking the way, but realize that shadows travel underground through the many tunnels. Ryunosuke wonders if they should go out and look for another entrance, but Ginjiro doubts there is one, at least not for humans, as the path ahead is no longer a normal tunnel, but looks like natural cave. Ginjiro shares that his grandpa told him about the Hiruko cave, a giant cave under Hitogashima. Until halfway through the Meiji period, there used to be an entrance that would show up at Hitogashima port during low tides. However, during the Sino-Japanese war, the army sealed it up. Its said that the cave is where Hiruko settled in after washing ashore long ago. Ginjiro suggests they speak with Karikiri and they would also need metal cutting tools to proceed. Ryunosuke then hears something and they hide. They see Tetsu and Mio coming and Shiori eating the metal bars, allowing them to continue.
Ryunosuke and Ginjiro proceed and reach the cave with sea anemone, which makes Ryunosuke realize they are all shadows. Shiori then appears and Ryunosuke explains that she must acted being killed, but escaped through the cracks and went underground. As Shiori reveals she knows Ryunosuke's name, he realizes its Heine who is using Shiori's memories. The shadow parent also appears and wants to know where the body with Mother's right eye is, but Shiori states she read Ryunosuke and Hizuru's mind, but they don't know. Ginjiro states they should run as they are the ones being hunted and that this isn't a shadow of a human. Shiori warns the shadow that Ryunosuke's shifted, about two seconds ahead. The shadow then shoots at Ryunosuke, but Ginjiro jumps in and takes the bullet. He then proceeds shooting at Ryunosuke, who manages to escape, but also gets shot. Looking at the blood, the shadow states its dark, which means he hit the liver and Ryunosuke won't have much to live.
Ryunosuke is heavily injured and loses consciousness, so he switches to Hizuru. Tetsu then appears and Hizuru asks him about Mio, but he explains a monster took her. Hizuru wonders about his gun, but Tetsu guesses he dropped it when he tried to shoot the baby monsters, but tripped and then ran. Hizuru tells him that was the right decision and asks him to carry her deeper in the cave as she no longer can walk on her own.
As they go deeper, they reach Heine and Hizuru shoots the head of the shadow parent, freeing Shinpei. She knows she has one more shot and shoots at Shinpei, but the shadow protects him with a shield and shoots and kills Hizuru. However, that was enough for Shinpei to be able to take his poison and kills himself.
- Hizuru's surname Minakata means "south/southern/southward/southwardly" (南方).