User blog comment:Sky-Dragoon-Twilight/Are the Wall Titans allies or enemies?/@comment-25358468-20140702053837

For one, we should put into consideration that they are Titans. The only 'good' Titan that we know of is Eren. Considering the complex structure of the walls, it was probably already pre-planned that these Titans would be made for the sole purpose of being destroyed. To me, it seems as though the creation of the walls was to force humanity into a cage simply for the Titans to crush them further.

Also, there are flaws in some of your hints for them being enemies. They obviously have been in there for a LONG time, and naturally would want to wake up and maybe move about or something, probably wrecking the walls in the process. The Titan could just be acknowledging Mikasa. And I don't see at all how #3 on your enemies list could somehow contribute to them being the antagonists here.