Mangas

Neko me Kozou
Cat-Eyed Boy is a half-human, half-monster child who mostly resembles a human, and therefore cannot live in the demon world. He lives hidden in the shadows of the human world, hated by both demons and humans. But wherever he goes, awful events occur. Humans interact with demons, but for the most part the humans that appear to act more evil than the monsters. Cat-Eyed Boy acts like Trickster, saving the innocent and helping the wicked receive the punishment that fate metes out. The stories are mostly tales of revenge and retribution for the evil acts people do. The series is broken into 11 individual stories, full of extremely grotesque and disturbing images.
漂流教室 -  Hyōryū Kyōshitsu -  Hyouryuu Kyoushitsu -  The Drifting Classroom
From Viz: Out of nowhere, a Japanese elementary school is transported out of the world they know, and into a nightmarish wasteland. Have they gone to another planet, or is this toxic world actually a vision of Earth's future? Soon, the students and teachers must struggle to survive in impossible conditions, besieged by terrifying creatures and beset by madness. Part Lord of the Flies, part post-apocalyptic science fiction, The Drifting Classroom (1972-1974) is a classic can't-put-down manga series. It was adapted into a Japanese live-action movie (1987).
14 Sai, 14 Years, 14 Years old, 14岁, 14歳
A SF/horror manga that takes place in 2200. At a chicken manufacturing company, a certain chicken transforms into a supermutant named Chicken George. And so, a nightmarish journey through a twisted version of the future unfolds 
神の左手、悪魔の右手 -  Kami no Hidari-te Akuma no Migi-te
The 6 books contains 5 horror stories related to a primary school kid named Sou. Sou has an ability to foresee supernatural events in his dream and even make changes that would eventually happen in the reality. The 5 stories are the Eroded Scissors, the Disappeared Rubber, ,the Tongue of the Spider Queen, the Black Picture-book and Shadow Dead. All of the scary stories are linked by his unique experience.
神の左手、悪魔の右手, God’s Left Hand, Devil's Right Hand, Kami no Hidari-te Akuma no Migi-te, Left Hand of God, Right Hand of the Devil
The six books contains five horror stories related to a primary school kid named Sou. Sou has an ability to foresee supernatural events in his dreams and even to make changes that will eventually happen in reality. The five stories are the Eroded Scissors, the Disappeared Rubber, the Tongue of the Spider Queen, the Black Picture-book, and Shadow Dead. All of the scary stories are linked by his unique experience.
わたしは真悟, ワタシハ シンゴ, I Am Shingo, My Name Is Shingo
Two elementary school pupils, a girl named Marine and a boy named Satoru, fall in love and are blessed with a rather unorthodox child which happens to be a robot. This robot is called Shingo and the story recounts how its mind develops and how it travels the world in pursuit of its ‘parents’ whom it has never had a chance to meet.
おろち, Orochi: Blood
Orochi is a girl not of this world, that much is clear. Among a few other unique qualities of her, she is immortal. We follow her through the monstrosities she witnesses in her ongoing life; the terrors and horrors of this world considered 'supernatural', the real, true meaning of 'vain' and a few mysteries that are, perhaps, inexplicable, to name a few.Though they do not happen to her in particular, she does try to help out of the goodness of her heart.For the better or for the worse, that much is unclear. 
洗礼, Baptism, Baptism of Blood