Yandere

Yandere (ヤンデレ)

A Japanese term for a person who is initially very kind, loving, caring, and gentle to someone (or at least innocent) they really, truly like and care about a lot before their purely intenseromantic love, admiration, and devotion becomes mentally destructive in nature, often through overprotectiveness, violence or brutality. The term is derived from the words yanderu (病んでる) meaning a mental or emotional illness, and deredere (でれでれ) meaning to show genuinely strong romantic affection. Yandere characters are mentally unstable, and sometimes are incredibly deranged and are not mentally sane, often using extreme violence and/or brutality as an outlet for their emotions. The usage of the character type has led to criticism over the amount of violence in works such as School Days, a classic story of a romantic love triangle gone dangerously wrong. Although the character type has been used in anime and manga since Mobile Suit Zeta Gundam in 1985, conscious use of the term only began to be around the turn of the millennium. A classic (and rather extreme) example of yandere is Yuno Gasai, from the manga/anime Future Diary, who is prone to kill anyone who may interfere with her obsessive passion for the series protagonist Yukiteru Amano (or just even be near him without any romantic contact). Yandere are usually, but not always, female characters, and are usually depicted as villains, making them anti-heroines at best but often the only evil teammate when on the good guys' team. For example Rolo Lamperouge from the Code Geass series can be considered a yandere for his ruthless devotion to the series protagonist Lelouch (who himself rises in arms against his father and his empire to create a better world for his little sister), as his affection grows to the point he will attempt to kill even those who are close to Lelouch in order to not be replaced. More good (and otherwise Anti-heroic) examples would be Belarus from Axis Powers Hetalia, or Hatsune Miku and Megurine Luka in the song "Scissorloid". Western/non-anime or manga characters that are similar in concept to a Yandere such asAnnie Wilkes in Misery fall under the Abhorrent Admirer trope. Sometimes, they can just be played in a comedic, usually exaggerated, context.

Yuno Gasai 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.

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.