Yuno Gasai

"Don't worry, Yukkii... I will (ahn) protect you."

- Yuno Gasai

Yuno Gasai is one of the main characters in Mirai Nikki. Along with being one of the twelve diary owners, she is also in the same class as fellow diary owner Yukiteru Amano. At climax of the series however, she became major antagonist once her true nature is revealed.

Personality
Yuno's personality is an ambiguous one, for the most part she is a sweet, feminine and sometimes shy girl when around Yukiteru Amano. 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 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.

However, she was not always insane. Her brutal personality is a result of circumstances surrounding 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. This was the beginning of her changes, as she later became quite lonely and sorrowful. So from the point onwards of 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, and threatened to kill Tsubaki Kasugano, and immediately panicked that Yuki's friends Aru Akise, Hinata Hino, Mao Nonosaka and Ouji Kosaka would take Yuki away from her, forcing Yuki to calm her down and announce their "relationship".

History
Yuno Gasai 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 what led her to 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 Mirai Nikki.

Diary & 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 killed them two, even though she was severly 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.

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.
 * 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.