Board Thread:Manga/@comment-5239435-20160910030604/@comment-5239435-20160910041518

But the Titans kept trying to attack the people in the Walls long before the fall of Wall Maria (if my theory holds up, this leave the issue of how the Shifters were unaware of the Walls and what lay within them for so long) and your idea doesn't explain why Grisha's actions back then which only hindered the Titan Shifters, why the Reiss were unable to control or destroy the humans from the more advanced society, or why the Reiss were unable to control the very Titans they created according to your theory.