Yuno Gasai

Yuno Gasai (我妻 由乃, Gasai Yuno) is the main female protagonist of the Future Diary series. She is the Second in the Survival Game and she is the owner of the "Yukiteru Diary/ Diary of future love".

Appearance
Yuno Gasai is a young girl with pink eyes and long pink hair styled in pigtails, two hanging as frontal locks featuring a pair of red bows, and the back pigtails left bare. Her most common attire consists of a blue shirt with a ribbon on her chest accompanied by a blue skirt with high socks, but her wardrobe changes occasionally throughout the series.

Personality
Yuno's personality is ambiguous. For the most part she is sweet, feminine, and sometimes shy when around Yukiteru. But, this masks her dark and sanguinary side—ruthless, cold and calculating. She has little, if any, problem with using others for her goals: her and Yukiteru's survival. She will resort to cruel and usually violent methods, most of the time coming out of nowhere, that generally end in bloody deaths, of either a Diary Holder or their followers, effectively making her a Yandere.

Her brutal personality mostly results from abuse inflicted by her mother and the absence of her father, which finally ended with their deaths two years prior to the Survival Game. This was the beginning of her changes, as she later became quite lonely and sorrowful. This is shown in her somewhat morbid habits of talking to her parents' dead bodies, telling them about her day and claiming she will bring by Yukiteru. She even took their heads with her when she trapped Yukiteru in a hotel, and when Aru Akise moved their bodies, she became angry and said her parents were sleeping and that he woke them up. These events also show her complex feelings about her family. Although she wanted them to feel and understand the pain she experienced because of their abuse, she essentially just feels deeply betrayed by them. She wanted them to be a happy family, but because of their neglectful behavior and their deaths, she felt like her life had no purpose.

Thus, when Yukiteru told her they would get married when they grew up, he unwittingly became a pillar of support that gave her much-needed stability. Her obsession with Yukiteru grew to escalating proportions to the point that she was willing to harm those whom she believed would take Yukiteru away from her, be they friends, rivals, relatives, other girls, etc.

She was prepared to resort to violence if Yukiteru's mother ever opposed her (which did not happen), stating that she did not "need her tools." Furthermore, she threatened to kill Tsubaki Kasugano, and immediately panicked that Yukiteru's friends Aru Akise, Hinata Hino, Mao Nonosaka, and Ouji Kosaka would take Yukiteru away from her, forcing Yukiteru to calm her down and announce their official "relationship", much to Yuno's joy and his own despair. At one point she even kidnapped Yukiteru and held him hostage because she was so terrified that another diary user would kill him. Aru has stated that Yukiteru provides a stabilizing influence in her normally chaotic and violent life.

Despite her insanity, Yuno has shown some reservedness to killing. This is shown when, after Yukiteru calls her his girlfriend, she instantly lets Hinata go when she intended to slit her throat. The fact that she did this rather than killing her anyway to ensure that there was no chance Yukiteru would fall for her suggests that she doesn't actually enjoy killing; she merely does it because she sees no other option. It is shown many times in the series just how deeply insecure Yuno truly is when she says her life would not be worth living if she could not be the center of Yukiteru's world. Her crippling fear of losing him is notably the only thing that can cause her usually disturbing composure to crack.

In the third world, the Third World Yuno seemed to be very nice and calm, possibly because she still had love for her parents and there was no survival game for them to participate in. This allowed Yuno to stay mentally sane. However, as a side effect of receiving her First World self's memories, it is implied that she might still remember some of the things that occurred in the first world as she states that she feels as if something is missing.

Diary & Abilities
Her diary is the Yukiteru Diary, which tells her everything about Yukiteru in intervals of ten minutes. While this means that her diary is basically useless by itself, if combined with Yukiteru's Random Diary that predicts only Yukiteru's surroundings, they can cover each other's weaknesses, making the two a fearsome duo. Even while the diary does not help her much by itself, Yuno can more than enough make up for it with her cunning intelligence, which has saved both Yukiteru and herself multiple times. She quickly formulates most of the plans the pair use to save themselves from the attacks of the other participants. Yuno is also very proficient at quickly determining the weaknesses of certain diary users, like Yomotsu Hirasaka and his blindness, or discovering that Tsubaki Kasugano's followers were pretending to be dead waiting to ambush them.

She is also skilled in setting traps, for example when she booby-trapped an abandoned hotel with multiple tools, such as electronic locks, concrete (gas in the anime) and even a sickle from an elevator (also in the anime). Her intelligence, her greatest asset, is displayed when she manages to outwit her opponents such as the very formidable Akise.

Yuno is shown to be quite resourceful. For example, she uses a shard of glass as a mirror to check the position of Minene Uryu during her bombing attack and a pair of stones against Yomotsu to root him out among his copycats.

In addition to intelligence and cunning, perhaps her most fearsome ability is demonstrating proficiency with different types of weaponry. These include knives, axes, swords, pistols and submachine guns. She is also fairly knowledgeable of poisons and drugs, although she rarely uses them. She has also demonstrated to be quite skilled in infiltration, as she has on more than one occasion entered a building unnoticed even while it was surrounded by the police.

Despite her childish appearance, Yuno has demonstrated impressive feats of physical strength, seen when she freed herself from two boys her age pinning her arms down. Another time is when she broke free of two Omekata Cult members when Tsubaki kissed Yukiteru. She killed them too, despite being severely weakened by the excessive amount of physical activity performed at that time, and subsequently chopped off Tsubaki's right hand with one strike.

Yuno also possesses divine powers from winning the first Diary Game and inheriting the throne of God. An example of such power is moving enormous structures through her will alone, such as when she tried to crush Yukiteru.

History
Yuno was adopted by her parents at a young age, her umbilical cord left to her as a present from her original parents, but was kept at the orphanage. Yuno's life was a happy one for several years until the strain of money began to emotionally and psychologically affect her parents. Yuno's father stayed away at work until the late hours and barely interacted with his family. Yuno's mother began to abuse her, wanting her to become the "perfect citizen," eventually locking her in a cage and timing everything she did, from sleeping to eating. Yuno's mother went to the extreme, leaving Yuno to starve and at times force-feeding her inedible materials, although it is implied in the anime that Yuno did this to herself to survive. While Yuno's father objected to his wife's severe treatment of Yuno, he did little to nothing to stop her. In the anime, Yuno's mother was ill and believed she was a terrible wife and mother, and believed punishing Yuno was her only way to earn happiness.

Eventually, Yuno snapped and managed to imprison her parents in the cage as punishment. However, she neglected to check in on her parents and they starved to death. Not removing the corpses from her house, Yuno began to act like they were still alive and talked to them, her home's electricity cut off due to unpaid bills. Now with nothing left to live for, Yuno fell into despair, to the point as was put in detention at school to write up her dreams for the future. Not having any dreams, Yuno turned to the only other person in the classroom: Yukiteru. Asking him what his dreams were, Yuno learned Yukiteru wished to go stargazing with his parents who had recently divorced. His dreams seemingly ruined, Yuno suggested seeing the stars with him. While Yukiteru objected to going with her instead of his family, Yuno proposed becoming his "bride". Believing Yuno to be joking, Yukiteru agreed but only when the pair grew up. However, in Yuno's view, she believed Yukiteru was serious and her whole life became focused on him. Observing him from afar, Yuno stalked Yukiteru. A week after their meeting, Yuno learned Yukiteru had a love letter, planning to give it to fellow student Moe Wakaba. Realising her chances to be with Yukiteru were in jeopardy, Yuno dressed herself up in a pink rabbit costume to stop Yukiteru from giving Moe the letter. Her attempt ultimately failed, but Moe kindly rejected Yukiteru's feelings towards her. Relieved, she kept stalking him.

The Survival Game
At the beginning of the manga, Yuno is introduced as the ideal student, with good grades and popularity. Already having her diary, Yuno kept an eye on Yukiteru until April 23rd when Deus activated the survival game. On April 24th, Yuno realizes Yukiteru has gained his Future Diary and creates a clay model of Muru Muru to leave on her desk and clue in Yukiteru. She then approaches him after school. Yukiteru runs off in terror, much to Yuno's surprise, until he flees into an elevator of a building. Yuno catches up and joins him in the elevator to save him from Third.

Yukiteru tries to pull out a throwing dart to defend himself, only for Yuno to kiss him full on the mouth, stopping him. Yuno explains the survival game, how she and Third are diary owners, and reveals that her phone focuses entirely on Yukiteru's actions. She averts Yukiteru's future by sending the elevator to the top floor instead of the fourteenth, where Third would have killed him had she not intervened. On the roof Yuno swiftly formulates a plan and instructs Yukiteru to destroy Third's diary using his throwing darts. They hide when Third appears on the roof. Yuno catches Third off guard when she runs out in front of him, allowing Yukiteru to throw a dart and pierce Third's phone, erasing him from existence.

Later, Yuno, Yukiteru and the other diary owners are gathered by Deus who explains the rules of the game. Afterwards, Yukiteru finds himself alone in the Cathedral of Causality, Yuno appearing behind him and vows to protect him no matter what, terrifying Yukiteru with her adoring look of joy.

Attack of The Ninth
After sending forty text messages to Yukiteru, Yuno is thrilled to be in his company again. The next day, Yukiteru approaches Yuno to ask for help in the game, although she departs to a P.E. class with the promise to talk to him later. However, Minene Uryu, the Ninth diary owner, arrives to kill Yukiteru. Yuno attacks her with a fire extinguisher and manages to save Yukiteru from the first bomb exploding in the middle school. Yuno promises Yukiteru to protect him. Afraid of dying, Yukiteru plays along with Yuno in order to protect himself and the two share a kiss. Sneaking through the school, the duo use their diaries to evade most of Minene's bombs but eventually are lured into a trap and caught in a blast. They survive but Yukiteru laments over his decision to be a bystander, however, Yuno reveals she has been watching him for a while and promises him that the other students and staff members are his friends. The two make it to the other side of the school, only for several students including Ouji Kosaka to ambush Yukiteru and drag him outside to be sacrificed to Minene.

Yuno is taken into a classroom where she watches Yukiteru falling into despair. Realising she lied to Yukiteru, Yuno vows to protect him. She frees herself from her captors and races out of the school, causing all of the motion-sensor bombs to go off until she eventually leaps out a window and tries to launch a surprise attack on Minene. At this point, Kurusu Keigo, the Fourth diary owner, has arrived to aid Yukiteru. Yukiteru charges at Minene, Yuno using her Yukiteru Diary to help Yukiteru avoid the landmines between him and Minene. Minene kicks Yuno away, leaving Yukiteru to use his common sense to dodge the final mine and wound Minene in the eye with a dart. Minene retreats on a motorbike using her Escape Diary. Later, Kurusu forms the Future Diary Alliance with Yukiteru and Yuno. Yuno reads her diary, finding the "Happy End" entry on July 28th, predicting that she and Yukiteru will come together as one.

Cult of The Sixth
Kurusu arranges for Yukiteru and Yuno to visit Sakurami City's amusement park in order to lure out Minene. Yukiteru and Yuno spent the day together, Yukiteru observing how Yuno did have a normal side after all. Yuno tries to go to the planetarium, but Yukiteru deliberately avoids it, choosing to go on the nearby Ferris wheel instead. Yuno confronts Yukiteru about his odd behavior, reminding him of their past encounter and the promise they made go stargazing together and become a couple, much to Yukiteru's shock. Yuno gives Yukiteru a kiss on the forehead afterward.

Yukiteru escorts Yuno to her house, although Yuno invites him inside. The electricity is out, and Yuno disappears into the kitchen to prepare an apple for her and Yukiteru to share. Yukiteru wanders off into the pitch black house to find the bathroom but comes across the sealed off room where the three corpses are. Reading the entries in his diary which only briefly note the door, Yukiteru decides to experiment and alter the future by looking inside the room. As he opens the door, all of the Future Diaries are completely rewritten. Yukiteru opens the door and finds the three corpses inside, altering the planned out future of the survival game and nearly destroying Deus' Cathedral of Causality. Yuno finds Yukiteru, horrified at what has happened, her diary's "Happy End" vanishing. Yukiteru flees her home in terror, running to his own house and locking himself inside, where he collapses by the door to catch his breath and regain his energy. Yuno follows, suddenly looking through the letterbox and wishing Yukiteru a good night.

The next day, Kurusu arrives at Yukiteru's house to pick him up, but as Yukiteru tries to tell him about the discoveries of last night, Yuno appears telling Yukiteru not to give away "what happened". Kurusu immediately assumes the two got up to something private and hops into the car, Yuno giving Yukiteru an innocent smile. Yukiteru, still cautious, hops into the passenger seat but has Yuno staring at him from behind all the way down the highway. Kurusu explains that Minene was captured overnight by the Omekata Temple cult, led by priestess Tsubaki Kasugano who is said to be able to predict the future through clairvoyance. They agree to meet the priestess in order to obtain and seize Minene.

When they arrive at the cult, Yuno watches Yukiteru as he approaches a pond while Kurusu talks to Orin Miyashiro. She catches him when he falls on his back, and finally accompanies him when Kurusu calls them. Tsubaki meets them and agrees to an exchange: she would hand over the Ninth in exchange for the First, since her diary has predicted her Dead End that night and he has escaped from the Dead End twice. Yuno immediately disagrees, but Yukiteru agrees to the deal and goes with Tsubaki.

That night, the cult followers fall into a deep state of hypnosis and become puppets for the Twelfth diary holder. They begin their attack against their leader, setting her chamber on fire. Armed with an axe, Yuno attacks and kills various followers to protect Yukiteru, but then she notices him running towards Tsubaki to save her. She catches up with him quickly and tells him that he has to either leave Tsubaki behind and join her or he would die. However, he tells Yuno he wasn't going to leave her behind, and hurries to her cage, leaving behind a crying Yuno.

Luckily, Kurusu was able to put down the fire by turning on the sprinklers, saving Tsubaki, Yuno and Yukiteru. However, the cult followers were still under the control of the Twelfth, so Yuno decides to lead Yukiteru (and Tsubaki, after he insisted on saving her too) towards the exit and leave the place. On the way, however, they are intercepted by the Twelfth himself, who is disguised among other four who look exactly like him. The five Twelfths race towards the trio, but Yuno (remembering the Twelfth was blind) turns that information in her favor to detect the real Twelfth and kill him in the spot with a swing of her axe.

With the Twelfth dead, the cult followers regain consciousness and Tsubaki reveals her true colours as she captures Yukiteru and Yuno. Revealing she planned this all along, Tsubaki kisses Yukiteru in order to taunt Yuno, which immediately provokes her rage. Yuno sets herself free by killing the men who were holding her and is able to grab her axe and swing it at Tsubaki. She barely saves her diary, but loses one of her hands to Yuno's axe. While she screams in pain, Yuno gives her diary to Yukiteru and pushes him out of the way, letting him escape instead.

The exhausted Yuno is dragged into the temple where the enraged, now one-handed Tsubaki contemplates what to do with her captive. Acknowledging she has to lure Yukiteru back, Tsubaki sets up a microphone and instructs her male followers to strip Yuno of her clothes and rape her like they did to her, while speaking to Yukiteru over the microphone and speakers to come rescue Yuno before she is molested. Yuno screams that she wants to lose her virginity to Yukiteru ("I was saving myself for Yukkii!"),and after thinking about her while in hiding, he decides he cannot leave her, and he charges into the temple clumsily, throwing a fire axe around. Yukiteru wraps Yuno up in his jacket and confronts Tsubaki, ultimately forced to damage her Clairvoyance Diary and eliminate her from the game. Yuno hugs Yukiteru's legs and cries. Later the two are seen in the back of a police van, Yukiteru confused by why Yuno stalks him and he takes her face in his hand and kisses her.



The Fifth's Game
Yukiteru goes to meet his mother, Rea Amano, at the train terminal where she is finally arriving home from work, leaving the house unguarded. Yuno breaks into his house by using a mallet and a roll of shipping tape, preventing the glass from shattering but breaking it just enough to unlock the door and enter the house. To his horror, Yukiteru discovers that Yuno has broken in and quickly attempts to hide her from his mother, but when he finds her cleaning his room and rearranging all of his books (including his stash of naughty magazines), Rea meets Yuno. Yukiteru is quickly off-put when he finds that Rea likes Yuno and supports their relationship, so much that she allows her to stay the night, in Yukiteru's room. Yuno quietly reflects to herself that she is glad she didn't have to do anything to Yukiteru's mother, and that her "tools" would not be useful here. This quickly turns out not to be the case, however, when Rea informs them that she is bringing home a little boy whose parents were both victims of the Omekata cult suicide.

This boy turns out to be Fifth, Reisuke Houjou, a Future Diary owner who wants to kill both First and Second. After trying and failing to kill Yuno several times,(First attempt was to poison the salad that Yukiteru and Yuno was eating) Reisuke quickly becomes entertained with her, and starts to put his cunning skills to work. After Yukiteru discovers that Reisuke is Fifth, he refuses to fight him and tells Yuno to stop fighting him as well, opting instead to try to find out where his Diary is, so that his mother will not be involved. Yuno ignores him and tries to kill Fifth anyway. While Yuno is chasing down Fifth, she accidentally hits Rea in the back of the head with a mallet, knocking her out and causing Yuki to become enraged. To make up for it, she promises Yukiteru that they will find Fifth's Future Diary and take it away from him instead, as he had originally planned, but they are unable to find it.

Yuno finally realizes that Fifth's Future Diary is being mailed back to them, and Yukiteru gets his hands on the envelope first, but unbeknownst to either Yukiteru or Yuno, Reisuke booby-trapped the envelope with poison gas, which releases into the house instantly and causes Yukiteru to collapse. While Yuno moves Yukiteru to safety, Fifth is able to get away, and his game begins. Reisuke reveals that he has the antidote to Yukiteru's poison in his bag, which he is running around with, provoking Yuno to chase him down. Yuno is able to overcome all of Fifth's traps in order to corner him, but is electrocuted when Fifth turns on all of the water upstairs and floods the stairwell, then breaks a lamp to send the electric current into the water. At first, Yuno is incapacitated, but Yukiteru saves her life by throwing a dart at Fifth, and resuscitating Yuno by breathing into her mouth. Yuno gets back up and fatally stabs Fifth.

However, after being defeated, Reisuke gives Yuno a warning about her future with Yukiteru: there can be only one survivor, and they will have to eventually try to kill each other. Immediately after Fifth dies and disappears, Yuno collapses again, only for both she and Yukiteru to be saved by Ninth.

Tenth's Trap
Yukiteru and Yuno are relocated to a different school after Ninth bombed their old one. Here, Yuki is reunited with his former friend, Kousaka, who slams his name the second he walks in because of the terrorist incident. This is when Hinata and Mao Nonosaka show up, both aiding Yukiteru. After the morning's festivities, Yukiteru is invited to hang out with the group at the scene of a murder. Yukiteru, oblivious to any danger and eager to hang out with his new friends, happily joins along, taking a silent, begrudging Yuno with him. While the four of them have fun, Yuno sits on the sidelines. It is heavily implied that she is thinking about killing Yukiteru's new friends, especially when she traces the word "Die" in the ground with her shoe repeatedly.

While the trio are hanging out, Yukiteru's Future Diary suddenly changes, revealing Hinata's death. Yukiteru rushes to the scene, but is too late to find Hinata, who had apparently been mauled by a pack of murderous dogs. Aru Akise arrives on the scene and reveals that he has been watching Yukiteru since the beginning when the group see the same dogs, who in turn see the group and start getting ready to attack. Yukiteru and his friends run to a nearby building surrounded by glass windows. The dogs attempt to break in, but Yukiteru reveals the truth about his Future Diary just in time to order his friends around to stop the dogs in synchronized order. Mao, who initially appears impressed, suddenly comes around to Yukiteru's side and steals his phone in a nonchalant fashion before holding a knife to his throat, as Hinata comes in behind them. After giving a short speech, revealing that she holds Tenth's diary, and is actually after the diary that she believes belongs to Akise.

Hinata is challenged by Akise to a gamble: if he wins, he gets Yukiteru's diary back, and if he loses, he will give up his own. By using Yukiteru's diary's weakness against Hinata, at Yuno's request, Akise is able to defeat Hinata in the gamble, winning back both Yukiteru and his diary, as well as revealing that he never had a diary. However, when Yukiteru is being released by Mao, Yuno rushes forward, pulls out her knife and stabs her. Hinata is left alone to take care of Mao while Yukiteru and his friends run away. Not content to leave her unattended, and highly upset with the outcome of their situation, Yukiteru turns back around to prove to Hinata that he meant to be her friend, and Yuno follows. However, when they get there, Yuno immediately ran up to hold Hinata at knifepoint for her diary. This is where Yukiteru declares his relationship for Yuno, in an attempt to get her to calm down. Yuno is ecstatic, but Yuki has his reservations.

Immediately after this, Karyuudo Tsukishima, Hinata's father, gives his final speech to his daughter via the dog's intercom before revealing that the man who had come to kill him was Fourth, Yukiteru's next enemy. Immediately after, Fourth shoots Tenth in the back of the head and kills him.

The Fourth's Betrayal
Instead of working with Yukiteru and Yuno to stop the survival game (and with Ninth to apprehend other players), Kurusu decides to break the alliance with them to kill them and become God himself. He devises a plan in order to kill Yukiteru and Yuno, without committing a crime himself, so that he can still use his Diary after killing them. Fourth provokes Yuno into committing a crime by playing a game of Russian roulette with Yukiteru during his interrogation process, causing Yuno's diary to change. In response, Yuno knocks out two detectives with a fire extinguisher and steals their guns, using them to attempt to kill Fourth before he can pull the trigger on his last round and kill Yukiteru. She succeeds in saving Yukiteru's life but fails to kill Kurusu. After a heated chase, Yukiteru and Yuno escape the police office, but are now wanted fugitives who have attempted to murder a police officer.

After spotting Fourth's wife, Naoko Kurusu, whom they had met in a rehearsal wedding ceremony not too long before, Yukiteru and Yuno follow her to the hospital, where Uryuu Minene is waiting for them. After a few bombs go off, Minene agrees to call a truce between the three, revealing that she is also being hunted down by Kurusu. Minene takes Yukiteru and Yuno to the hospital room that Naoko was headed for, where they find her and Yoi Kurusu, Fourth's son. Here, they discover that Yoi is dying, and that Kurusu wants to become God so that he can reverse time to save his son. Yukiteru, Yuno, and Minene form a new alliance, aiming to take down Kurusu, but all three of their Future Diaries are showing Dead End flags, indicating that Kurusu is coming for them.

While trying to escape the hospital, Ninth runs into Masumi Nishijima, Kurusu's second in command, and realizes how to defeat Fourth. After Yuno detonates a flashbang grenade in Fourth's face, thinking that it was a real grenade and preparing herself to sacrifice her own life for Yukiteru, all three of them are knocked out. Shortly after this, a bomb that Ninth had planted explodes, leaving Yukiteru, Yuno and Kurusu in a bombed-out shell of a hospital. Yukiteru picks up a gun and aims it at Kurusu, who is using Yuno as a human shield. Yukiteru manages to shoot Kurusu, despite his own Diary predicting Yuno's death instead. Not too long after this gunshot, Nishijima shows up with Ninth, who has a taped recording of Kurusu's voice, explaining how he has been breaking the law. This revelation allows Yukiteru and Yuno to escape, their criminal records wiped clean as well. Before breaking his own Diary, Fourth asks Ninth to take care of his son. Ninth agrees, and Fourth dies.

Rescue Operation
Being a couple Yukiteru and Yuno would plan on a trip for both disappearing for several days. Yuno on her desperation of being tagged by Akise and have her Happy End ruined decides to secretly kidnap Yukiteru and have him secluded so the two of them can be happy in the end.

Yukiteru's friends Hinata, Mao and Kousaka would be enlisted to help by Akise and Nishijima, as Yuno has hidden in an old residential area full of hotels some of them owned by her parents, and Yukiteru's friends would not alert her as much as the police. Yuno discovers that they are tagging her and eventually tricks Hinata into thinking Yukiteru escaped and sent a message asking for her, Hinata does arrive but Yuno attacks her and has her tied up. She uses the same trick to lure the rest of them, using a mannequin of Yukiteru to trap them in a room and bury them in concrete (gas in the anime). Yuno almost naked, tries to feed a barely conscious Yukiteru while Hinata confronts her about what she is doing, Yuno believing Yukiteru is content. She is interrupted by Akise who claims to Yuno he wants to negotiate with her and blackmails her with the corpses found at her home, planning to tell the police about them and asks her about the third corpse's identity. Yuno is at first enraged that Akise would defile her parents' corpses, but goes silent after hearing of the third one. She then bursts in hysterical laughter, repressing her memories in a fit of despair, while madly talking to Yukiteru that they are "weird people" and cuts communications. Eventually thanks to Kousaka he is be able to use the ventilation shaft and sneak into the control room where Yukiteru and Hinata are confined. Yuno, not knowing who Kousaka is, expresses shock that he has a Diary. Listening to his explanation, she deduces Kousaka is not very smart and tricks him into giving her the key to the control room and later that of Yukiteru's.

Throwing him the first key, Yuno uses the chance to pull out a crossbow while Kousaka frees Mao and Akise. Yuno coldly shoots him in the leg whilst pointing out his failure, however, before she can kill him, Yukiteru is freed by Hinata. Snatching the crossbow from Yuno, Yukiteru slaps her and stops her, saving Kosaka and freeing Hinata in the process. Seeing Yukiteru leaving with his friends, Yuno desperately tries to call out to him, however, an enraged Yukiteru tells her to go to hell. Sad and alone Yuno resolves that Yukiteru is not safe without her and goes after him.

The Seventh's Battle Of Love
After the breakup, Yukiteru would soon be a target of both The Seventh duo Marco Ikusaba and Ai Mikami as well as The Eighth, Kamado Ueshita and her orphan army. Yukiteru would be put under protection by Akise who uses Kosaka's house as a stronghold with a system to nullify the Apprentice Diaries of Kamado. Yuno however infiltrates the house and renders the jamming system useless in an attempt to prove herself worthy of Yukiteru again by protecting him. Yukiteru quickly deduces her intentions and thinking her to be more of a danger than an asset decides to have Yuno come to him albeit have her hands tied. With the police and Nishijima overwhelmed by The Seventh pair, Yukiteru has to run for his life with Yuno, Hinata and Mao.

Hinata and Mao would eventually be injured by them while Yuno suggests they should leave them die and run away. Yukiteru is cornered in a room. Worried about Hinata and Mao and the incoming Seventh, with little choice Yukiteru decides to free Yuno. The Seventh pair catch up to them and with their Apprentice Diaries rendered useless by Akise who turns the jammer manually, the duo use their real diaries. Ai throws a knife which Yuno blocks, being praised by Yukiteru. She becomes so happy that she successfully parries each and every knife thrown by Ai, leaving the shocked Sevenths with no choice but to retreat. Yukiteru worried about his friends decides to follow them, but the house is put on fire by an orphan of Kamado. Yukiteru and Yuno eventually encounter The Seventh and the pairs battle under fire. Yukiteru not knowing if he can trust Yuno leaves her be without helping her, which causes Yuno to be defeated by Ai and Marco. Enraged by Yukiteru's behaviour, Marco takes both their diaries thinking they can be useful alive while also giving them another chance. Given the terrible loss, they would be rushed to the hospital.

While in the hospital, Yuno escapes her room to check on Yukiteru who is reunited with his father Kurou Amano and play sport competitions courtesy of Minene. Yuno stalks them with knife in hand as she is unaware who Kurou is, but finds herself relieved that he is Yukiteru's father and that she does not have to resort to violence.

Eventually however, Yuno would stalk Kurou and discover his plans to destroy Yukiteru's cellphone to have his debts paid by The Eleventh, John Bacchus as she overhears his conversation with him by phone. Yuno quickly warns Yukiteru about this but he's distrustful, while Yuno attempts to kill him but Yukiteru stops her from taking drastic actions while Yuno asks him who he trusts more.

Yuno would receive a call from Marco, telling her to do not harm Kurou or risk her Diary to be destroyed along with Yukiteru's since Kurou can lead them to The Eleventh. They order the three of them to go to Sakurami Tower which they comply, Yuno using this chance to see to Kurou's real intentions. Reaching to the cathedral within the tower, Kurou tries to get a hold of Yukiteru's cellphone, but is beaten by Marco. Yukiteru rushes to rescue his father to no avail, and during the distraction, Kurou reaches Yukiteru's cellphone and breaks it, only to find out it is a fake. With his intentions crystal clear, Yuno rushes against Ai, and slashes at her flowers, which had the true Diaries hidden. Eventually the tower is bombarded and the floor collapses with Yukiteru falling, Yuno and Kurou try to aid him, and Yukiteru prefers Yuno over his father.

The two of them decide to retreat with The Seventh duo following. While Yukiteru is not sure of their chances given their last battle, Yuno reprimands him that it was his fault for not trusting her that they were defeated and tells him her plan. The Seventh duo reach Yuno who is alone while Yukiteru broadcasts he will fight hidden. Marco enraged attacks Yuno and disarms her knife with her teeth, with Ai is soon to restrain her, while Marco decides to go after Yukiteru. Ai points that they cannot win two vs one, to which Yuno agrees, revealing Yukiteru having hidden close to them instead of the broadcast room. Yukiteru throws a dart against Ai, and Marco warns her to avoid it, however Yuno uses the chance to slice her throat, with Yukiteru disapproving of her extreme violence and that taking her Diary was the best choice. The tower starts to collapse further and they have to use parachutes, one is used by Kurou who escapes the tower. Debris falls on them and Yukiteru, Yuno and Ai are trapped.

Ai tells them that they have lost since Marco is still alive and outside. Yuno agrees but plans to use Ai as hostage to force Marco to take them out, Yukiteru however believes this to be extreme. Marco does try to help but not because of Yuno's threats but because he loves Ai. During this time Marco uses this chance to reprimand Yukiteru for his cowardice in letting Yuno do all the dirty work, and Yuno for being selfish and do whatever she wants rather than cooperate with Yukiteru. Hearing this Yukiteru decides to help Marco and asks Yuno for her help, while initially unsure she's encouraged by Yukiteru who wants to believe on her and she helps. Escaping the debris they take the remaining parachute since Marco does not want to live without Ai. Yukiteru and Yuno descend, Yukiteru wanting to make things right with his family and asking for Yuno's support, to which she agrees. After descending the two encounter Nishijima, and is witness to how Yuki's mother corpse is being taken by an ambulance.

The Eleventh's Kingdom
While Yukiteru mourns the death of his mother, Yuno prepares him sandwiches and a message to cheer up. The next morning while Yukiteru follows his father in an attempt to prove he's guilty on his mother's death, she is brought by Nishijima to questioning regarding the third corpse on her house, but she does not reply and simply leaves. A brief time later she reads on her diary that Yukiteru is under attack by John Bacchus' men, and rushes to help him all the while cursing Nishijima for his questioning and thinking she will kill him if she is late to save Yukiteru.

While Yukiteru confronts Bacchus' men by himself, Yuno arrives at the shrine and kills the last one. Heartbroken by the loss of his parents, Yukiteru tells Yuno that he will become God even if he must kill her. In response, Yuno embraces Yukiteru and kisses him, claiming she is more than willing to die for him.

Days later the two are missing and during a meeting of participants The Eleventh proposes that the two are to be eliminated from existence. Before Deus does so, they appear in The Cathedral of Causality embracing each other, while Yukiteru reveals Bacchus to be the Eleventh, Sakurami City's mayor and reveals that the two were gathering information of him through The Random Diary, prompting Deus to remove the shaded cover on their identities. As soon as Yukiteru finishes his speech, Yuno congrats him for looking so cool while she changes clothes in front of him and gives him the next step of her plan in a script, as she tells him that John most likely closed Ueshita's orphanage to corner her to take possession of her Blog Diary and create an army of Apprentice Users. As Yukiteru begins to doubt if he truly can go ahead, Yuno launches herself towards Yukiteru kindly embracing him and telling him that she won't forgive him if he isn't serious about what he said before about becoming God.

The following day Yukiteru and Yuno manage to ally themselves with Ueshita and her army of orphans. While Yukiteru explains the plan and the two sides prepare to ambush John, Yuno signals Yukiteru. Soon after the two bands ambush John and are successful in killing most of his guards, however John activates a jammer on his car which renders the Apprentice Diaries useless. Both Yukiteru and Yuno use this chance to kill the orphans and then attack Ueshita and John. The two of them escape while Yukiteru and Yuno follow via car. Yuno shoots at the car but the bullets miss. Yukiteru suggests John diary must be like his own that predicts his surroundings, and Yuno attempts to gun John himself, but also misses. Dumbfounded Yukiteru desperately rams his car and the two parties fall without injuries. Yukiteru and Yuno corner John but Akise arrives with the help of Minene, the distraction causing Nishijima to shoot at Yuno's gun to disarm her. Akise reveals that the Yuno there is a fake as the third corpse found in Yuno's house is in fact the real Yuno Gasai, positively identified via DNA test with an umbilical cord left at the orphanage the real Yuno was adopted from. Yuno desperately cries and asks Yukiteru to believe her, while he briefly separates from her, Yuno desperately tries to call to him. Yukiteru soon protects Yuno from John's gun, and John soon takes his leave. Yukiteru and Yuno decide to leave while Akise tries to convince him otherwise, but Yukiteru claims Yuno is Yuno and they leave.

Yukiteru and Yuno decide to remain hidden until Minene strikes at John's. They use her as bait to successfully infiltrate with Yukiteru saving Minene while Yuno creates a ruckus, killing many of John's men with a submachinegun and slicing the remaining ones with a katana. Yuno soon takes civilians hostage to have a leverage over John. Yukiteru, at this point, instructs Yuno to rescue his friends while Minene and Yukiteru deal with John. Yuno successfully rescues Kousaka, Mao and Hinata from death by killing John's men, while she makes her way to Ueshita to kill her. She find her but is being protected by Akise who blocks her attack with a tonfa. Enraged, she attacks again, but her diary predicts that Yukiteru wrote his last words (a trick used by him on purpose to force Yuno to come to his aid and change the future) and soon rushes to Yukiteru's side, while Yukiteru proves victorious over Minene by using the noise from his diary to distract her for long enough to have the faster pull of the trigger.

Yuno soon reaches him, discovering that with her last act, Minene attempted to destroy the vault door so that Yukiteru could kill John. Yukiteru claims Minene died for him in vain, mourning her loss, but Yuno encourages him to destroy the Holon so that Minene's death is not in vain, which he does. As soon as he walks away, Yuno uses the retinal scanner to successfully open the vault and decapitates John; or shooting him in the head in the anime. Yukiteru asks her how she was capable of killing John and she replies that she ambushed him while he left the vault. Yukiteru predicts that Yuno opened the vault in the anime, and does not question her. The two proceed to leave to Yukiteru's house to sleep after they endeavour. Yukiteru awakens, only to see that Yuno is half-naked sleeping besides him with his hand on her breast, which Yuno forced on purpose, unnoticed. Yukiteru screams in surprise while Yuno greets him, but the dumbfounded Yukiteru demands she put on her clothes. The two decide to have breakfast as the only one remaining is Kamado who is under Akise's guard and as such easy to reach. While the two contemplate what to do later, Yukiteru's house starts to collapse.

The End Begins
Following John's demise, Yuno and Yukiteru witness several voids that are destroying the world. Yuno concludes that Deus is dying and therefore they must act fast, encouraging Yukiteru to become God so he can return the dead back to life. Yukiteru and Yuno soon go to Akise's house, where he reveals that he has been given an Apprentice Diary by Kamado in exchange for protecting her.

Yuno asks about The Eighth's location, but Akise merely asks her to leave, saying that he wants to speak with Yukiteru. Enraged, she tries to stab Akise, only to find that he has a protective vest; she attempts to use a stun-gun, but Akise blocks it with a rubber glove. He reveals the powers of his Detective Diary to both of them; it can predict the future even if other diary holders try to change it. Realizing that this is a distraction, Yuno tells Yukiteru to follow his friends and Kamado while she handles Akise.

As Yukiteru goes on the chase, Yuno battles Akise, only to be defeated and pinned to the ground. Seeing no other escape, she stabs herself to force Akise to heal her - he would otherwise risk making enemies with Yukiteru. Akise reluctantly does so before leaving to find Yukiteru, giving Yuno a chance to call him herself. She tells him that she was stabbed by Akise and that his friends are betraying him, a claim his diary seems to confirm. Moments later, Yuno's diary reports that Yukiteru has shot Hinata with his gun, prompting the Second to cackle maniacally and declare that anybody who tries to separate Yuki from her should die.

Despite her injuries, Yuno manages to track down Yukiteru, finding him being confronted by Akise over her deceptions. She tells Yukiteru not to believe a word he says, flying into a rage when Akise deliberately kisses Yukiteru. Declaring that Akise will die here and now, Yuno charges to meet the Observer as he uses a pipe from the rubble as a weapon. With his Detective Diary, Akise avoids Yuno's attacks before breaking her diary...

...but Yuno simply keeps going and slashes his throat, telling Yukiteru that Akise destroyed a fake diary. She brushes off his confusion by urging him to find and kill Kamado before she gets away again, and ends up stabbing the Eighth when they find her buried under rubble. Shortly afterwards, they notice Akise staggering towards them, typing a message on his phone. Suspecting danger, Yuno decapitates Akise as he approaches Yukiteru, but the headless body keeps going. In desperation, Yuno slices Akise's phone in two, but she is too late to stop Yukiteru from reading the message on its screen.

The Final Battle
Now the only diary owners left alive, Yuno and Yukiteru live their final days before July 28th (when the world is destined to end, as well as the date of the "Happy End" shown in Yuno's diary). Yuno becomes upset that her advances towards Yukiteru are brushed off (such as her invitation for them to take a bath together) and Yukiteru realizes that despite her insane tendencies, Yuno really does love him. Yukiteru decides to sleep with Yuno on the 27th, changing the "Happy End" future to a day early. Afterwards, Yukiteru asks Yuno why she lied to him about the powers gained as the winner of the Survivor games, commenting on the strange message Aru showed him before he died. Clearly upset over this, Yuno asks Yukiteru to explain what Aru's message said; upon learning that Akise discovered that the present Yuno was in fact from another timeline, she suddenly attacks Yukiteru with an axe.

Yukiteru is saved by Muru Muru, now acting as God in the wake of Deus's demise. Against Yuno's wishes, she shows Yukiteru flashes of Yuno's past, confirming that she is indeed from a previous timeline where the Survival Game was held. In this "first world", Yuno and Yukiteru were the only remaining candidates as the world teetered on the brink of collapse. Unwilling to kill each other even to become God, they decided to commit double suicide and let the world be destroyed. However, Yuno tricked Yukiteru by hiding the pills in her mouth instead of swallowing them, believing that she could revive him with the powers of a God. After gaining Deus' powers, however, she discovered that she cannot bring the dead back to life, leaving her devastated. At the suggestion of Muru Muru, Yuno uses her new powers to travel back in time to when Yukiteru was still alive, crossing the dimensional borders and creating a new timeline from scratch. Sneaking into her second self's house, Yuno butchers her counterpart with an axe. The second Yuno writes the Japanese phrase for "Help me!" in blood before dying; afterwards, Yuno is given her counterpart's Yukiteru Diary by Muru Muru (who had similarly imprisoned and replaced her second world self).

After Yukiteru has seen these events, Muru Muru releases him from the visions so that he can confront Yuno. Yuno attempts to kill him, but Minene, revealed to have survived her death thanks to Deus' interference, joins in to help Yukiteru. Deciding to cut her losses, Yuno once again leaps back in time with Muru Muru, creating a third world with the intentions of starting her vicious cycle all over again.

Yukiteru and Ninth follow, arriving two years earlier at the home of the third world's Yuno. After freeing her from her cage, Yukiteru and the third Yuno are carried away to the middle school by Minene, where the first world Yuno ambushes them. While Minene battles Muru Muru, Yukiteru hides the third Yuno and then battles the first to seize her diary. Yuno angrily vents at her boyfriend, angered that the universe won't let them be together. She orders Muru Muru to remove her bracelets, unlocking her true superhuman powers to defeat Minene. With the former Ninth out of the way, Yuno captures Yukiteru and imprisons him in an illusion-based dream world so he can be happy, but he is horrified to learn that he cannot speak Yuno's name - Yuno revealed she does not exist in the illusion world. She finally admits that their relationship was a sham on both sides - Yuno was emotionally dependent on Yukiteru, and he depended on her as a bodyguard in the Survival Game - but despite her words, she finds herself unable to kill Yukiteru. Explaining that the illusion world is a way for Yukiteru to move on without her, Yuno leaves him to his prison, placing Moe Wakaba as his make-believe girlfriend.

After sealing Yukiteru, Yuno attempts to kill the third Yuno to take her place, but first informs her younger counterpart of the nightmarish fate that awaits her. However, to Yuno's surprise, her third world self optimistically denies such a life, convinced her parents will sort things out. As a horrified Yuno realizes how twisted she has become, her counterpart asks if she loves someone; admitting that she does, Yuno tries to kill her third world self with a knife. However, Yuno's father intervenes to protect his daughter, quickly joined by Yuno's mother and Kurusu enters, aiming his gun at Yuno.

Seeing her other self's parents acting so protectively, Yuno realizes that Yukiteru deliberately changed the timeline to prevent the Survival Game, improving the lives of the would-be participants in the process. Finally accepting how much she loves him, she suicidally charges at the Gasai family, provoking Kurusu into firing his gun at her. However, she is saved when Yukiteru breaks out of the illusion world, accompanied by the second world's Muru Muru, who was imprisoned by her first world self. While Muru Muru stops Kurusu's bullet and defeats her first world counterpart, Yukiteru embraces Yuno and asks her to kill him to save the second world.

However, Yuno instead stabs herself with her knife, having come to genuinely love Yukiteru. She shares one last kiss with the distraught First, complimenting him on his improvement before passing away. The second world Muru Muru promptly declares Yukiteru the winner of the Survival Game, abruptly transporting him back to his timeline and leaving Yuno's body behind. The first world's Muru Muru is able to salvage her former master's memories in the form of a crystal before being imprisoned by her third world counterpart.

Redial
In the Future Diary Redial, it is shown that the third world's Yuno, is a sane and sociable honors student with a better relationship with her parents. However, she has strange dreams (actually fragments of her previous self's memories) that feature an unknown person who she feels a bond with, causing her to watch the third world's Yukiteru. As she finishes watching him through a telescope, she is confronted by the third world Aru Akise and Reisuke Houjou for stalking, allegedly on a hunch pointed out by Yukiteru's girlfriend, and finds herself repeatedly intercepted while attempting to watch Yukiteru. Yuno sends Yuki a letter to meet up, but her letter is intercepted by Akise, who directs the demon Gremory to arrest Yuno.

However, the first world Muru Muru is able to communicate with Yuno through the keychain on her phone, directing her to dodge the attack and enter the Archives where she is held. Akise confesses his personal jealousy of Yuno as the object of Yukiteru's affections, directs Gremory to save her from falling back into reality, and supports her as she goes deeper into the Archives. The third world's incarnation of Muru Muru attempts to stop her, but Minene is able to occupy her long enough for Yuno to reach the center of the Archives. Using the sword she took from Akise as a key, she opens the sphere and meets with the Muru Muru of the first world, now bearing features similar to Yuno herself.

It is revealed that Muru Muru had been calling the third world's Yuno in an effort to implant the memories of her first world self in her body, effectively "reviving" the original Yuno; however, viewing Yuno's memories had given her a change of heart. Regretting her selfish actions, she warned Yuno that the memories were harsh and painful, but Yuno happily accepted them, believing that they would allow her to find the person in her dreams. With that, she took the core into herself, gaining the memories of Yuno's life in the first and second worlds; with her prior development and the memories of her happy life in the third world, she was able to avoid going insane this time.

Now effectively her first world self in her third world's body, Yuno used a mallet to shatter the boundary between the third and second worlds, reuniting with Yukiteru in the void that remained of the latter. She told him that she would explain what happened later before they left to fulfill their promise of stargazing together.

In an epilogue, it is revealed Yukiteru and Yuno lived together through four more different timelines.

Trivia

 * The characters of her last name mean "I" (我) and "wife" (妻), respectively.
 * Yuno's birthday is November 16th.
 * Her first name is based on Juno, the Roman goddess who was wife to Jupiter. Like her namesake, Yuno is extremely jealous of any woman who goes near Yukiteru.
 * Yuno's "Yandere Trance" at the end of Sign Up has become an internet meme, with internet users editing Yuno's face to look like other characters from numerous series.
 * Yuno has three character theme songs: The first is "RED Love " performed by Faylan; the second is "Happy Fate " by Matsui Yousei and sung by Choucho; and third, shared with Yukiteru, is "My Wish Lives in the Future ", sung by Yuno's voice actress Murata Tomosa.
 * Both of Future Diary 's anime openings subtly foreshadow the revelation that Yuno killed herself.
 * In the English dub of the anime, Yuno calls Yukiteru by affectionate nicknames like "sugarbear" and "sweetie."
 * Yuno was a contestant of the International Saimoe League's 2012 season.
 * Yuno translates to English as “hot water”, while Gasai translates to “tactics”.