User blog comment:Speculation no Kyojin/Episode 25 - The Titan in the wall/@comment-162.72.174.142-20140521211702

What I thought was that the  titans were some sort of population control that got out of hand. The people who built the walls might have put the titans inside to prepare for the day that the humans tried to break out. I mean, imagine finally breaking through a wall to find that the very thing you have been hiding from for centuries inside?