Attack on Titan (manga)

Attack on Titan is an anime about humanity's struggle against Titans, man eating giants. A little over 100 years ago, the titans appeared, and pushed humanity to the brink of extinction. Humanity retreated into stronghold with mighty walls the titans couldn't breach. Since then, humanity has been locked in a stalemate against the Titans. Shortly after the story begins, a colossal titan appears, and destroys an outer wall. It is known for Anyone Can Die, so don't get too attached to anyone.