In The Attacking Giant, the original setting is that the human living in three walls is the only human in the world, while the earth outside the walls is full of giants, and there is no other human life.

As a result, with the development of the plot, Kaiju and Chaoju destroyed the city wall and put a large number of giants into the city wall, and people once again remembered the horror of being dominated by giants. The death of the protagonist's mother leads to the protagonist's desire to slaughter the giant. In order to slaughter the giant, the protagonist trained on the city wall and joined the reconnaissance corps. With the beginning of the first battle of the reconnaissance corps. Allen was swallowed up by a giant, and everyone thought Allen was dead. However, Allen broke out the ability to become a giant, which led to the origin of the giant and the identity of Allen's father. With the interpretation of the plot, the identities of the super giant and the armored giant were also exposed, which triggered the news of the giant camp and later led to the human kingdom except the Three Walls. It also triggered another war between human beings.

Allen's ancestor giant and attack giant, the strength of two giants, make Allen have more powerful power than other giants.

With the gradual development of the plot, people found that the essence of the giant is that human beings injected giant serum and then became giants. The great disaster of mankind is caused by mankind. The power of the wisdom giant can be passed down through plunder, which is also the reason why Allen's father invaded the home of the ancestor giant and successfully gained the ability of the ancestor giant by eating the ancestor giant.

This is also the scariest truth in The Attacking Giant. The catastrophe caused to mankind is actually caused by human beings themselves, who have pushed themselves into a corner.