Several hundred years ago, humans were nearly exterminated by giants. Giants are typically several stories tall, seem to have no intelligence, devour human beings and, worst of all, seem to do it for the pleasure rather than as a food source. A small percentage of humanity survived by enclosing themselves in a city protected by extremely high walls, even taller than the biggest of giants. Flash forward to the present and the city has not seen a giant in over 100 years. Teenage boy Eren and his foster sister Mikasa witness something horrific as the city walls are destroyed by a super giant that appears out of thin air. As the smaller giants flood the city, the two kids watch in horror as their mother is eaten alive. Eren vows that he will murder every single giant and take revenge for all of mankind.
In Victorian-era London, on the night of Ciel Phantomhive's tenth birthday a fire destroyed his manor and killed both of his parents. In a moment of death Ceil strikes a deal with a demon, his soul in exchange for revenge. This demon becomes his butler and calls himself by name of Sebastian Michaelis, to protect and serve Ciel until the deal has been completed. One month after the fire Ciel returns from being missing, with his new butler Sebastian. Ceil is now the head of the Phantomhive corporation, handling all business affairs as well as the work as the Queen of England’s guard dog and looking for his parents murders.
GOSICK takes place in 1924 in a small, made-up European country of Sauville. The story centers on Kazuya Kujo, the third son of a Japanese Imperial soldier, who is a transfer student to St. Marguerite Academy, where urban legends and horror stories are all the rage. There he meets Victorique, a mysterious yet beautiful and brilliant girl who never comes to class and spends her days reading the entire content of the library or solving mysteries that even detectives can't solve.
On the island country Hinomoto, humans hide themselves in fortresses called "stations" against the threat of zombie-like beings with steel hearts known as "Kabane." Only armored locomotives known as "Hayajiro" go between the stations.
Steins;Gate is set in the summer of 2010, approximately one year after the events that took place in Chaos;Head, in Akihabara. Physical locales of Akihabara like the Radio Kaikan building can be spotted in the game. According to Chiyomaru Shikura, who headed the planning of Steins;Gate, Akihabara was chosen because it is an easy place for acquiring hardware parts, which makes it the ideal place for people interested in inventing and tinkering with things. The notion of time and time traveling are the main themes of the game. The concept of cause and effect is featured prominently in the game as the protagonist travels back in time numerous times to perform different actions in an attempt to alter what has happened in the future.
The year is 1939 - it was then that the Neuroi appeared. Nobody knows where they came from or what their ultimate agenda is, but the fact remains that their attacks drove people out of their towns and cities. In order to take arms against them, humanity develops a new anti-Neuroi weapon called the "Striker Unit." Using the power of magic to fight against the monsters, this new device enhances and amplifies the power of female magic-wielders. To use this device, young witches from all over the world have been brought together to form an elite task force unit called the 501st Joint Fighter Wing, commonly known as the "Strike Witches."
Ordinary high schooler Yoshiharu gets pulled into a time slip to the warring states period. There he meets Nobuna Oda - not Nobunaga, Nobuna. In this world, all the famous warlords of the era are female. Nobuna recruits Sagara, who she dubs "Monkey," to help her in her quest to rule the world.
In a world where humans and non-humans have not yet been separated, the kingdom of Leones is protected by the Holy Knights, powerful magic users both revered and feared by the people. Supposedly the strongest, most fearsome of these knights, the Seven Deadly Sins, betrayed the kingdom and made enemies of all the other knights. Queen Elizabeth doesn't believe this story, and sets out to find the Sins - but when she meets the first Sin at a tavern, his name is Melodias, and he's nothing but a boy in charge of the pigs.
It is the early 20th century, and Raishin Akabane is a student puppeteer from Japan, who has come to the Walpurgis Royal Academy of Machine Arts in England to study the emerging field of Machinart: a combination of magic and technology with military applications. He is accompanied by a girl named Yaya, who is actually his Automaton: a living machine doll powered by magical circuits specialized in hand-to-hand combat. In the Academy, there is a combat tournament exclusive to the Top 100 students and their automata, to decide who shall be bestowed with the title of "Wiseman", the greatest puppeteer.