Titan Monsters

Over 100 years before the beginning of the story on an alternate world, giant humanoid creatures called Titans suddenly appeared and nearly wiped out humanity, devouring them without remorse or reason. What remains of humanity now resides within three enormous curtain walls. Inside these walls, humanity has lived in uneasy peace for one hundred years; many people growing up without ever having seen a Titan. This all changes when one day, a giant 60-meter (200 ft)-tall Colossus Titan mysteriously appears after a strike of lightning and breaches the outer wall of the Shiganshina district, a town at Wall Maria, allowing the smaller Titans to invade the district. An Armored Titan smashes clean through the gate in Wall Maria, forcing humankind to abandon the land between Wall Maria and Wall Rose..

The Titans are giant humanoid figures ranging between 3–15 meters (10–50 ft) tall and are usually masculine in body structure but lack reproductive organs. Although they do not appear to need food, they instinctively attack and eat humans on sight; it is mentioned that they derive their energy from sunlight. Furthermore, the Titans also do not have a proper digestive tract; once they have eaten their fill of human prey, titans will vomit their meal into large, slimy balls. Finally, their skin is tough and strong, and they regenerate quickly from injuries, save for a weak spot at the nape of their neck

The soldiers use a tethering system called Vertical Maneuvering Equipment acting as a grappling system, allowing them to jump onto (and swing from) walls, trees, or nearby buildings to attackthe Titans with dual swords. However, despite it being the soldiers' primary line of both offense and defense against the Titans, it is useless in open and flat terrain like fields.