By default almost everyone likes a happy ending. However, there are those who feel that the anime should be more realistic, since not everybody can be happy in life. Here are some anime which deviate from the 'and they lived happily ever after' conclusion.
(Warning! this article may contain spoilers)
Arguably one of the best anime of all time, the 37 episode Death Note anime series was co-produced by Madhouse, Nippon Television, Shueisha, D.N. Dream Partners and VAP studios. Even though the animation quality isn't very good (keep in mind the series was first aired in 2006), the plot will keep you on the edge of your seats at every point in the story.
The main character Light Yagami is a high school student and a prodigy with a strong sense of justice. One day he finds a notebook which enables him to use the power of a Shinigami (God of Death) to kill anyone whose name is written in the notebook, so long as he sees the person's face. Light decides to eliminate all criminals irrespective of their crime in order to build a world where crime does not exist. He dons the title 'Kira' and begins his journey to creating his ideal world while experimenting and learning about the power of the Death Note.
The entire anime deviates from the stereotypical anime setting, since the main character himself seems to be the villain, who is willing to sacrifice anyone in order to achieve his goal. Nevertheless, the plot took an unexpected twist in the end with Light being outsmarted by a highly-esteemed international consulting detective and being killed by his aide Ryuk (the Shinigami to whom the Death Note belongs to). The twists don't end there though, after the credits scene of the last episode, Light's devoted girlfriend Misa Amane commits suicide unable to bear the separation.
Guilty Crown is a 22 episode anime series produced by Production I.G studio, which aired from October 13, 2011–March 22, 2012.
Ten years after the outbreak of the 'Apocalypse Virus,' an event solemnly regarded as the 'Lost Christmas,' Shu Ouma a high school boy encounters a wounded girl named Inori Yuzuriha, the vocalist of a popular internet group Egoist, taking refuge at his film club's workshop. He obtains an ability called 'Power of the King' that enables him to draw out items called 'Voids' from other people, which drags him into the ongoing war between GHQ and Funeral Parlor.
Eventually, Shu and Inori fall in love with each other but their love is short - lived. In order to stop the 'Fourth Apocalypse' from destroying the world, Shu embraces Inori and activates his Void, absorbing everyone's Voids and taking all of the Apocalypse Virus onto himself. As he is about to be consumed, Inori sacrifices her own life to the virus, saving Shu.
Produced by Doga Kobo studio, Plastic Memories is a 13 episode anime series built around humanoids.
The story revolves around Tsukasa Mizugaki who manages to get a job at the Sion Artificial Intelligence Corporation (SAI Corp) which is responsible for the creation of 'Giftias'—highly advanced androids which are almost indistinguishable from normal humans. However, unlike humans, Giftias have a maximum lifespan of around nine years. Terminal Service One, the station Tsukasa was assigned to, is responsible for collecting Giftias that have met their expiration date, before they lose their memories and become hostile.
Tsukasa is partnered with a Giftia named Isla. She is a Terminal Service veteran and considered the best in Giftia retrievals. Tsukasa and Isla fall in love with each other, however Isla has almost reached the end of her lifespan. In the end, Tsukasa retrieves Isla knowing fully well that he will never see her again.