The strange man behind the attack of the giant

The Investigation Corps has suffered heavy casualties in all previous wall operations, but the loss of countless lives is just a sacrifice in vain. They can't get any useful information. All this stems from their "ignorance" of the world but if one day someone crosses the giant world with real memory, won't he be able to save everyone directly maybe the world has changed. Even crossing is like drinking water so easy cooling did it but easy to cool, from then on, it has really become easy to cool, cool and cool