Yuno Gasai

"Don't worry, Yuki. It'll be okay. Yuno's here to protect you. I'll do whatever it takes to keep you safe, because that's how much I love you."

- Yuno Gasai to Yukiteru Amano

Yuno Gasai is the main female protagonist of the anime/manga series, Future Diary (Mirai Nikki in Japanese). She is the second diary owner in the Survival Game and she is the owner of the "Yukiteru Diary/Diary of Future Love" and has an obsessive crush on Yukiteru Amano.

She is voiced by Tomosa Murata in the Japanese version of the anime and Brina Palencia in the English version, the latter of whom also voices Priscilla and Rikako Oryou.

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
"I'm the only friend you'll ever need, right?"

- Yuno to Yuki, while holding a knife to Hinata Hino's throat.

Yuno's personality is an ambiguous one: For the most part she's a sweet, feminine and sometimes shy girl when around Yukiteru Amano. However, this masked her darker side, which is that of a ruthless, cold, and calculating psychopath who has little, if any, problem in using others for her ends, which are her and Yukiteru's survival. She will resort to cruel and mostly violent methods that most of the time end in bloody deaths, of either the Diary Holder or any follower, effectively making her a Yandere at its extremes. She is also prone to jealousy, as she grew completely enraged when Tsubaki Kasugano and Aru Akise kissed Yuki in front of her, going so far as to call the former a whore in the dub.

It's later revealed that her insane, psychotic self was a result of horrific circumstances in her life, mostly the abuse she endured by her adoptive mother and the absence of her adoptive father, which finally ended with their deaths two years prior to the Survival Game. After that, she became quite lonely and sorrowful. When Yukiteru told her they would marry when they grew up, it was the pillar of support she needed, and her obsession for Yuki grew to escalating proportions, willing to harm those whom she believes will take Yukiteru away from her, such as friends, etc. This goes to the point that she considered resorting to violence if Yuki's mother ever opposed her (which did not happen), threatened to kill Tsubaki, and immediately panicked that Yuki's friends Akise, Hinata Hino, Mao Nonosaka and Ouji Kosaka would take Yuki away from her, forcing Yuki to calm her down and announce their "relationship".

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 suggests that she doesn't actually enjoy killing, but does it because there's no other option in her damaged mind. It's shown many times in the series just how deeply insecure Yuno truly is when she says her life wouldn't be worth living if she couldn't be the centre of Yuki's world. Her crippling fear of losing him is notably the only thing that can cause her usually disturbing composure to crack.

History
Yuno began life fairly normally. The only strange part was her own adoptive mother's obsession with her success. This went as far as extreme regulations including a strict diet, and even locking her in a cage if she did bad or failed in one of her classes. This is when Yuno snapped, killing both of her adoptive parents in the original Earth. After joining up in the survival game, she and Yukiteru work together and defeat all the other diary owners. However, when it was just the two of them left, they decided to ingest cyanide and commit twin suicide. Yuno, however, only pretended to consume hers, hoping to bring back Yukiteru after she replaced Deus. However, after discovering that even Deus could not bring back the dead, she decided to restart the Earth, killing the Second Earth's Yuno and her adoptive parents, leading to the events in the series.

Diary and Abilities
Her diary is the Yukiteru Diary, which tells her everything about Yuki in intervals of 10 minutes. While this means that her diary is basically useless by itself, if combined with Yuki's Random Diary that predicts Yuki's surroundings, it can cover Yuno's weakness and protect Yuki, making the two a fearsome duo. Even while the diary does not help her much by itself, Yuno can more than enough make for it with her great and cunning intelligence, which has saved both Yuki and herself in several times. She makes up most of the plans the duo uses to save themselves from the attack of the other participants, as well as quickly determinate the weaknesses of certain diary users, like The Twelfth's blindness, or discover that The Sixth's followers were pretending to be dead to ambush them. She is also skilled in traps, seen when she booby trapped an abandoned hotel with multiple tools (this is best seen in the anime), such as electronic locks, concrete (gas in the anime) and even a sickle from an elevator (also in the anime). Her intelligence being her greatest asset.

Yuno is shown to be quite resourceful, using a shard of glass as a mirror to check the position of Minene Uryu during her bombing attack, as well as a pair of stones against The Twelfth to discover him amongst his copycats.

Her perhaps most fearsome ability along with her great intelligence is her mastery skill in basically all types of weaponry, mostly blades, such as knives and axes, and during the attacks against The Eighth and The Eleventh, to be a skilled swordswoman, and using firearms such as a pistol and a machinegun with lethal proficency. She also is fairly acknowledgable of poison and drugs although she uses them in few times. She has also demonstrated to be quite skilled in infiltration, as she has in more than one occassion entered a building unnoticed even while it was protected by the police.

Also despite her feminine appearance, Yuno has demonstrated impressive feats of physical strength mostly when angered, seen when she could free herself from two boys her age holding her in both arms, as well as free herself from two Omekata Cult members even when The Sixth kissed Yuki and she killed them both, even though she was severely weakened by the excessive amount of physical activity performed at that time. Also during the second attack against The Eleventh, she was capable of slicing up a person in half with a katana.

All in all, those who have ever faced and lived to tell the tale, have acknowledged her as a fearsome opponent and can be considered one of the most powerful participants.

Legacy (Mirai Nikki Redial)
As seen in OVA, 3rd world Yuno gained a happy life with her parents because of climax of Mirai Nikki. But then, is bothered by something which missing in her life. That's until she enter corridors of Cathedral of Causality for the first time thanks by Minene. Both were intercepted by Akise and 3rd world Muru-Muru. Yuno escapes while Minene hold Muru-Muru, and eventually found confined 1st world Muru-Muru. From this Muru-Muru she eventually learned the truth about Survival Game, Amano Yukiteru, and her insane 1st world counterpart.

After learning everything, she quickly found Amano Yukiteru and they embraced each other, receiving their happy ending together.

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 was wife to Jupiter.
 * Yuno is known in the anime world as the Queen of Yandere.
 * Like her namesake, Yuno is extremely jealous of any woman who goes near Yuki.
 * Yuno's "Yandere Face" 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 is sometimes mistaken for the main antagonist of the series. This proved to be false, as she never had any true desire to hurt Yuki and only wished to have a happy end with him (which she finally gets at the end). She's instead a seriously messed-up, misguided anti-heroine/anti-villainess and a pawn of the series' true main villain.