User blog comment:Gourgeist/Who Is The Beast Titan?/@comment-25448721-20141006054615

Oh cool you posted it! :D

I don't really have any ideas myself because I got really confused at this part of the manga and I need to reread it xD

But I have heard other peoples' theories: I read this SUPER long theory post on a blogspot blog a while ago (it was a theory on pretty much the entire plot of SnK, how the story started, and how it will end). They guessed that the ape titan is from the Homeland, where RBA are from, and that they are the oldest, first-created Titans, given the power to control normal titans for military reasons.

You would probably get really bored reading my summary of it, so you should go check it out! I think it's one of the best plot theories I have ever read for Snk

http://snktheories.blogspot.com/2014/08/attack-on-titan-shingeki-no-kyojin.html