User blog comment:Sky-Dragoon-Twilight/Are the Wall Titans allies or enemies?/@comment-108.224.88.87-20140702070232

My guess is that they were human who purposely transformed themselves into titans as kind of a self sacrifice and the original holder of the coordinate(maybe eren's dad) guided their actions to create the walls. Once trapped in the wall lost their ability to move and escape. My guess is the effectively act as normal titans but were specally created. and are stronger then the average titans.