Yuno Gasai

Yuno Gasai is the secondary protagonist of Future Diary, and the Second diary owner. Obsessed with Yukiteru Amano, Yuno comes off at first as a crazed stalker but is very devoted to Yuki. She possesses two personalities, one being a sweet, devoted girl, and the other a psychotic, obsessive and jealous girl. She has the "Yukiteru Diary".

Personality
Yuno's personality is an ambiguous one, for the most part she is a sweet, feminine and sometimes shy girl when around Yuki. This masked her darker side that is of a ruthless, cold and calculating sociopath who has little if any problem in using others for her ends, that is her and Yuki's survival, and will resort to cruel and mostly violent methods that most of the time end in bloody deaths, of either the Diary User or any follower, effectively making her a Yandere. While she's insane for most of the series, she was not always like that, and her brutal personality is a result of terrible circumstances surrounding her life, mostly the abuse she endured by her mother and the absence of her father, which finally ended with their deaths 2 years prior to the series. This was the beginning of her changes, as she later became quite lonely and sorrowful. It wasn't until she met Yuki who told her they would marry when they grew up, something at the time Yuki did not take seriously but for Yuno, it was the pillar of support she needed and from that point onwards, her obsession for Yuki grew to escalating proportions. Willing to harm those whom she believes will take Yuki away from here, such as friends, etc. This goes to the point that she considered resorting to violence if Yuki's mother ever opposed her, which luckily did not happen.

Later in the series as more background is given, her insanity is best understood. It is hinted that during the events of the 1st world, Yuno was not always the cold-murderer she was, as Yuki was seen protecting her, so she may have a more stable personality back then. Finally, after she wins the game and the cruel truth was revealed to her, that she and Yuki would never be together as she had wanted, she screams in despair. From this point onwards does her sanity turn into sorrow, with repeating the events of the game the only way she could ever be with Yuki, even if temporarily. For this means she will kill even Yuki, whom she still loves but cannot save, thus sparking conflict with herself. In the end her love proves superior and towards the end of the series, does her insanity and sorrow banish for good.

Plot Overview
It is revealed over the course of Future Diary is that there are three Yunos, originating from three different parallel worlds created when the first Yuno performs time leaps to the past. The first Yuno and the most prominent, travelled to the second world and killed her second self to replace her. She created a third world to kill her third self, but ultimately decided not to, sparing her third self.

Background
Yuno was adopted by her foster 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 forcefeeding her inedible materials. While Yuno's father was objective to his wife's severe treatment of Yuno, he did little to nothing to stop her.



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 Amano.

Asking him what his dreams were, Yuno learnt Yuki wished to go stargazing with his parents who had recently divorced. His dreams seemingly ruined, Yuno suggested seeing the starts with him. While Yuki objected to going with his family, Yuno proposed becoming his "bride". Believing Yuno to be joking, Yuki agreed but only when the pair grew up. However, in Yuno's view, she believed Yuki was serious and her whole life became focused on him. Observing him from afar, Yuno stalked Yuki until she was chosen for Deus Ex Machina's survival game as the Second owner, thrilled to see Yuki was the First owner.



The two participated in the game with the Fourth owner Keigo Kurusu as an ally until his own betrayal and death. Yuno and Yuki became the last two surviving diary owners. In love with one another, neither were willing to kill the other to become God. They decided to perform a double suicide, taking an overdose from medicine and seemingly died together. That was until Yuno was revealed to have faked her death, not swallowing the lethal medicine. Being declared the winner and the new God of Time and Space, Yuno wasted no time in resurrecting Yuki, only to discover it was impossible to revive the dead. Driven into despair and insanity, Yuno and the first Muru Muru performed a time leap back in time, creating the second world and arriving one year into the past.

At this point in the second world that the second Yuno had killed her parents, and was already emotionally attached to Yuki. The first Yuno stepped in and butchered her second self. Dying moments later, the second Yuno managed to write "Help me!" on the wall in her blood. Muru Muru imprisoned her second self away in Yuno's Illusion World, and gave Yuno her second Yukiteru Diary, allowing her to have an advantage over the other diary owners when the second survival game rolled around. Yuno began stalking the second and most prominent Yuki until the time for the second survival game came.

Reunion With Yuki
At the beginning of the manga, Yuno is introduced as the ideal student, having good grades and is popular. Already having her diary, Yuno kept an eye on Yuki until April 23rd when Deus activated the second survival game, although Yuno acted as though it was her first game and many of her future actions were a rehash of her previous ones until the game's predicted timeline is altered. On April 24th, Yuno realises Yuki has gained his Future Diary and approaches him for the first time after school, creating a clay model of Muru Muru. Yuki 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.

Yuki tries to pull out a throwing dart to defend himself, only for Yuno to kiss him full on the mouth, stopping him. Yuno explains about the survival game, how she and Third are diary owners, and reveals her phone focuses entirely on Yuki's actions. She averts Yuki's future by sending the elevator to the top floor instead of the fourteenth, where Third would have killed Yuki had she not intervened. Going to the roof, Yuno instructs Yuki 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 Yuki to throw a dart and pierce Third's phone, erasing him from existence.

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

Trivia

 * The characters of her last name mean "I" (我) and "wife" (妻), respectively.
 * Her first name is based on Juno, the Roman goddess who is wife to Jupiter.
 * Like Juno she is suspicous and jealous of anyone who tries to get close to Yukiteru.