Attack on Titan (進撃の巨人 Shingeki no Kyojin?, lit. Advancing Giant(s)) is a manga series written and illustrated by Hajime Isayama. It was first published in September 2009 and is serialized in Kodansha’s Bessatsu Shōnen Magazine.
The original Japanese title, “Shingeki no Kyojin,” has a dual meaning. The literal translation of the title is “Advancing Giant(s)” or “Attacking Giant(s)”, with giants being Titans in the context of the series. In this way, the title can refer to both the advancing threat of the Titans or to a single attacking Titan.

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 walling 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 one of the city walls is damaged by a 60 meter (196.85 feet) giant causing a breach in the wall. As the smaller giants flood the city, the two kids watch in horror the tragic events that follow. Eren vows that he will wipe out every single giant and take revenge for all of mankind.