|“||Articles of the deceased, though, are another matter entirely. I simply must bring back a spirit item imbued with the soul of it's owner! A vessel through which he or she can speak...||”|
—Aiko Niwa, Corpse Party: Blood Drive (CHAPTER 02『 Respective Desires 』)
Aiko Niwa (丹羽 亜衣子 Niwa Aiko ) is a student from Paulownia Academy High School, an intelligence agent, and a survivor of Heavenly Host Elementary School. She is a character first introduced in the Corpse Party: Book of Shadows light novel, and makes her first game appearance in Corpse Party -THE ANTHOLOGY- Sachiko no Ren'ai Yūgi ♥ Hysteric Birthday 2U.
Aiko is a teenage girl of above average height and below average weight. She has long, black hair with light blue highlights. Two blue ribbons are tied in it. Aiko seems to have an interesting fashion sense, wearing a gold necklace with a pink gem, and a short purple yukata with a red skirt underneath. She wears geta with long stockings tied with light blue ribbons.
In Corpse Party Cemetery0 and Corpse Party: Book of Shadows light novel, Aiko is seen wearing a normal Paulownia girl's uniform.
Aiko is an intelligence agent with interest in spiritual items and money. As a successful young woman, Aiko gives off a façade of cheerfulness, but underneath she is greedy and not someone to trust with anything. She is willing to align with good or evil depending entirely on which side benefits her more. As described by the closest person she has to a friend, Aiko is a gossip interested in other people's private lives, using her spiritual powers to her advantage in order to manipulate other people and find out more about them.
With all of her customers, Aiko exchanges information, but they must give her money in return, or a supernatural item of equal value. She turns dark when people do not fulfill their promises to her and seeks vengeance on them in harsh, unethical ways. Despite this, she does have a genuine care for the few friends that she has and mourns for their deaths and she feels sympathy for Sachiko Shinozaki. She is the younger sister of Kuon Niwa and often shows her anger towards her sister's controlling nature.
Corpse Party CEMETERY0 ~Kaibyaku no Ars Moriendi~
FILE #10: Girl Meets Girl
Naho and Akari Roen decide to get help from Aiko, as their case now has a corpse. Akari asks Naho about Aiko and later, about spiritual items. Aiko explains it to her and says to Naho that she will look for information on the case for a big price, but tells that if she finds any spiritual items, she will lower the price accordingly.
FILE #11: Rival
Naho is seen sitting in the school cafeteria, and Aiko sits next to her. The two have a little chat and then move on to the main subject revolving around the website for suicides. Aiko explains that Miku Sensu most likely was killed because she was the one who wrote down Shiori Izuru's. Aiko herself doesn't seem to be holding a lot of hope that Shiori is alive, even if her corpse wasn't found. Naho then pays the price to look into the case and the two depart.
Bonus File: Corpse Pa_ty
Aiko is the main character of the bonus file. She is seen walking down the street, acquiring a new spirit item: A pair of underwear that were the last possession of an underwear thief who fell down the balcony and died, which now had the ability to steal and manifest as the underwear that the person Aiko touches wears. She walks down the street, touching people and seeing what they wear for her amusement. Along the way she accidentally touches someone and sees that their underwear is a girly and frilly pair. She turns to see who is was, finding out it was Shougo Taguchi.
FILE #13: Night Under the Midnight Sun
Aiko goes back to talk to Naho, asking for the money on digging up the information. Naho gives her the envelope, and the two girls call it settled. Aiko then turns around to say something, but screams and tells Naho that she should be really careful. What she saw was a dead person behind the glass window starring directly at Naho.
LAST FILE: Memento Mori
It is revealed that Aiko was the one that warned Sayaka Ooue about Naho's position. Aiko appears later, cheering that the place is full of spiritual items. Aiko then joins Naho and Sayaka in exporting Akari into the hospital via the helicopter.
Corpse Party -THE ANTHOLOGY- Sachiko no Ren'ai Yūgi ♥ Hysteric Birthday 2U]
#1; The Shame on The River Kwai
Aiko appears as a commentator who was brought here by Sachiko Shinozaki. Naho Saenoki and Sayaka Ooue are both really surprised about it, but Aiko says that it's all alright, as she is more than happy to be here.
She then reappears through out the chapter, commenting on those who went to escape the place.
At the end of the chapter, she persuades Sachiko into giving Haruyuki Inumaru his prize for winning the race.
#3; My Greatest Feeling! Trans-Abandoned Bomb Shelter Ultra Quiz
After they are all transported to the underground bomb shelter when everyone wakes up they all realize that Kou is nowhere to be found. Aiko then takes out a piece of paper and says that it says something about Kou, but mocks Naho. She is then convinced by Shougo to read it. She says that Kou is the prize for the game. Suddenly the monitor turns on, and Kou is shown on the monitor along with Sachiko. Aiko is chosen as the one who looks after the group, as the prize they get doesn't actually concern her or Haruyuki. Aiko then reads the rules to the group, saying that they need to choose 427 points to win.
While Naho is mocking Shougo, Aiko will call Naho's "answer" incorrect, and they lose 50 points. It is then revealed that Shougo likes being constantly insulted by Naho, leaving everyone disgusted at him. After walking in the darkness, Shougo says that he hears footsteps and that he thinks it's Kou. Everyone calls him out and then yell at Shougo, saying to look out. He then gets hit in the head by the hammer, not having a scratch on him. It is then shown that Yoshikazu Yanagihori is hitting Shougo with a Pico-Ham (a plastic hammer that squeaks when you hit with it). Aiko question Naho on her remark that the hammer is different and says that it's a shame that she doesn't get to see it, as it's probably full of evil energy. Aiko then explains that no one is allowed to separate from the group or they will be bashed just like Shougo is, as the key to winning this game is teamwork.
After a while, Sayaka mentions that she knows this place so she might know where the quizzes are hidden, but Aiko explains that the dimension is different, so the place is most likely not the same. After a heated argument on which direction they should go, it is left for Naho to decide. After she chooses left, Aiko claims that she chose correctly and is awarded 10 points.
The group enters the dissection room, where Aiko says that the amount of hatred in this room is fascinating. Inumaru finds a bonus question in one of the bloody buckets and has to quickly answer the question. He says that there is ten buckets inside this room and wins 50 points. He gets hugged by Sayaka and Naho, who are both happy. He finds another question regarding pee-girls, and after thinking with the group answers that the one in mind is Yuka Mochida, which rewards them 20 points. After that Haruyuki finds a third question written in blood, questioning who in Byakudan Senior High School found the "Sachiko Ever After", after Aiko gives them the full names of the girls trapped here (as well as finding out about Shougo's fascination with little girls). Aiko, now angry that she was fooled by Shougo, says that she will curse his entire bloodline, and reveals that she holds a grudge. After some talking, Haruyuki answers that it's Emi Urabe and wins the group 50 points.
The girls go and enter the lavatories, leaving the boys outside and finding a question regarding the girls breast sizes. Sayaka and Naho both reveal themselves to be C-cups, but Aiko demands a lot of money for personal information. Sayaka tells Naho her plan, and the two of them grab each of Aiko's breasts. The two girls are then fascinated by Aiko's size, and everyone conducts that Aiko is the biggest of the three, which earns them 10 points. The group then finds more questions, one of them asking who is behind them (in this case Sayaka) right now. A blackout occurs and leaves everyone in pitch blackness. Once the light is back on Sayaka answers that there might've been a ghost behind her, which earns them 100 points. After that Sachiko leads them to the corpse pool, where Kou is hidden and gives them the last question: If only one of them can make it out of here, which one of them would deserve it the most. They all refuse to answer, saying that they don't want only one of them to make it out, which is the correct answer. Due to that, they win the game.
#5; The King and Us
Aiko reappears in this chapter, calling Sachiko "Sachiko-sama", to which Naho and Sayaka say that Aiko is totally under Sachiko's control. She then plays a maid for the group, bringing snacks, outfits for Naomi Nakashima and Naho and a game of "Twister".
#8; Today's the Day, Farewell
Aiko, along with Haruyuki, not belonging to Heavenly Host, says their goodbyes to Sayaka and Naho. Aiko then supposedly loses her memories of this event, along with the rest.
Corpse Party: Blood Drive
CHAPTER 00 『 A Faint Light 』
Aiko appears in the middle of the chapter, looking over Kisaragi Academy.
She later reappears at the end of the chapter, after Satoshi Mochida called her into the room. It is Aiko that told Ayumi's friends of her whereabouts and helped them. She then introduces herself to Ayumi and asks for the box that Ayumi acquired.
CHAPTER 01 『 Returning 』
Aiko meets up with Ayumi Shinozaki and Yoshiki Kishinuma in a cafe and discuss their discovery. Aiko questions the two survivors about Naho Saenoki and Sayaka Ooue. Ayumi tells Aiko that Naho's dead, but doesn't know anything about Sayaka. Yoshiki interrupts the two and asks why all of this matters, as Heavenly Host Elementary School was destroyed by them. Aiko then tells them that he is incorrect and that Heavenly Host still exists. Aiko then shows them a "thoughtograph" of a hallway in Heavenly Host, featuring what seems to be Yuki Kanno holding a hatchet and a book. The survivors question on how Aiko was able to produce a photo, so Aiko shows them the Everafter Stones, which were inside the red box that Ayumi found in the Makina Shinozaki's residence. She then explains to Ayumi on how Yoshie came to open up the Heavenly Host, or Nirvana. After some more explaining and talking, Aiko reveals that her plan is to make Nirvana a tour place, for which she could make some extra cash. This leaves both Ayumi, and Yoshiki surprised. Yoshiki then tells Aiko that she got the stones because Ayumi risked her life, so Aiko gives one of the stones to Ayumi.
CHAPTER 02 『 Respective Desires 』
Aiko is seen talking to herself in her room, saying that she is sorry that she had to lie to Ayumi about being able to bring her friends back to life. She then says that she hopes that she cannot wait to pack Naho's spirit into a spirit item and add her to her collection, adding that her hobby has turned her into a monster, yet she can't wait for it. She then picks up the only picture that she has of Sayaka, Naho and herself and realizes that her only wish is to talk to them one last time. Kuon walks in and they talk. Aiko goes to get a drink, but Kuon Niwa already brought a cup of barley tea for her. Aiko calls her constant ability to predict what people want off-putting and drinks the tea. They then talk about how Kuon can work as both a CEO and a teacher, to which Kuon says that she loves making people happy. Kuon asks about the Everafter Stones, but Aiko brushes her off. Kuon mentions that she's fallen in love with someone, But Aiko leaves.
She meets up with Haruyuki Inumaru outside of her house, Haruyuki expressing his worries about Sayaka, saying that he will definitely save her. Aiko says that there is a possibility that Sayaka is already dead, but Haruyuki says that it's impossible, denying the facts given to him. Magari Mizuki walks in on their conversation and congratulates Aiko for finding a way into the Nirvana so fast, as well as telling that she has no business there. Haruyuki remembers her as the girl who just transferred into their school this year. Magari then reveals to Aiko that Ayumi and Misuto Kiriya are already in the Nirvana, as well as threatens to kill Aiko if she doesn't hand her the stones. Aiko then mocks Magari and uses the stones, sending Haruyuki and herself to the Nirvana. Unfortunately for her, Magari manages to take Aiko's stones right before they are sent, leaving them with no way out.
Aiko wakes up in the second building's entrance and realizes that the stones are gone, as well as her hand being injured. Haruyuki appears behind her and says that he saw Magari taking them from her. Aiko then says that to escape they will need to find Ayumi before she leaves, but Haruyuki insists on looking for Sayaka. Aiko says it's dark, and she is about to get one of her candles, but Haruyuki turns on a flashlight he brought with him. While walking together, Haruyuki questions who Magari is, and Aiko asks him to keep a secret. She explains to him that Magari belongs to Martuba's Tomb and tells him to be careful about Magari from now on. Haruyuki enters the lavatories and finds a corpse. His scream alerts Aiko, who runs in. The two then are surprised by the corpse. Aiko then takes a ring owned by the victim and calls it a good spirit item, as it bears the grudges of the victim. Aiko shows her true cockiness and arrogance when she starts taking spiritual items without thinking about the feelings of those who owned it. They find that walls in Heavenly Host start to become meaty and twitch. They enter the music room and find that the sound playing inside was from spirits. After Haruyuki checks it out, the piano shoots into him, barely missing him. After that Haruyuki starts succumbing to darkening, Aiko seeing a ghost of another victim, who lets Aiko take the statue from his corpse to save Haruyuki.
The two then find their way into the bell tower, where they find a corpse of Yoshikazu Yanagihori, who was crucified. The two later enter the file storage room and find Shougo Taguchi's camera, which shows them that Naho and Kou Kibiki are both dead. Haruyuki breaks down and starts crying. The two then move on, looking for Sayaka. Haruyuki gets a call from her, so he runs off, finding a closet in the hall next to them, from which Sayaka's screams can be heard. Aiko stops him from running towards it, predicting it to be a trap. A moment later the door opens, and Sayaka's rotting corpse is revealed. Both of them break down in tears, Haruyuki soon after succumbing to darkening and turning into a beast. He says that it's all Aiko's fault and attacks her. She runs for her life but is tackled by him to the ground.
CHAPTER 03 『 Pain 』
Aiko appears at the end of the chapter, bloody from her previous encounter. She screams at Ayumi to run away from Sachi. Ayumi questions who she is, but Aiko runs up to her and explains that she found more pictures like the "thoughtograph", each with some other object in Yuki's left hand. Aiko demands Ayumi to use her Everafter stones to go back. Ayumi says that she doesn't have them anymore, and Aiko breaks down crying. Suddenly she is set on fire by Sachi, who laughs menacingly. Ayumi tries using water on her, but it only grows bigger. Aiko runs away screaming.
CHAPTER 06 『 Book of Shadows 』
Saved by her talismans, Aiko comes to the realization she will probably never see her sister again but decides to fight until her last breath anyway. While looking for the school infirmary, she finds herself in the clinic from Yoshie Shinozaki's home. That's when she discovers what she feared: Nobody can escape their destiny once they die in Heavenly Host.
Once reunited with Ayumi at the tower summit, Aiko reveals she has been using her the whole time for foolishly wanting to get her friends back. A little later while trying to prevent Misuto from using the sephiroth of knowledge she died.
CHAPTER 08 『 Ties Severed, Ties Mended 』
Aiko tries to prevent Misuto from the sephirot once again, but as she was about to meet her demise once again, she is saved by Ayumi holding the book of shadows. After subduing Misuto, Sachi appears and to everyone's surprise reveals, through Naomi's cursed eye, Yuka is also in Heavenly Host. They decide then to split into two groups, one that will stay behind to keep watch on Misuto and the other to rescue Yuka. Listening to her sister for once, Aiko stays behind with Ayumi and Satoshi, but this last one takes upon Ayumi's request and rejoins the other group. A little later Misuto escapes, punching Ayumi in the stomach and leaving the two girls behind.
CHAPTER 09 『 Imperator 』
After Ayumi recovers, she and Aiko go after Misuto who took the book of shadows. Aiko can't shake the feeling there is something off but then Magari appears, and she gives back to the two girls the Book of Shadows and Naho's hair clip. Aiko is overwhelmed with joy to finally be able to communicate with Naho through that spirit item. After some explanations from Magari on why she is helping them, Ayumi decides to continue alone and asks Aiko to meet up with the others, but she refuses because she doesn't want to let her sister down. They pursue their road but this time to find the core of the nirvana.
CHAPTER 10 『Reparations』
At the beginning of the chapter, Aiko tells Ayumi her backstory -her parents abandoned her giving her a lonely childhood and explaining why she likes the supernatural so much. Aiko travels with Ayumi to the door of the core of the Nirvana, but they stop just outside. Ayumi tells Aiko that she might get in the way, and tells her to stay. Though she means well, Ayumi's words hurt Aiko, but she stays back. After Ayumi defeats the core, she and all the others who are still alive flee the crumbling Heavenly Host.