User blog comment:MeDeoPal/On the Origin of Titans and Shifters/@comment-66.190.75.100-20140420233723

I honestly recommend reading this manga, it takes place before the fall of Wall Maria and gives alot of new information that isn't given in the series. It explains many things about titans that you wouldn't expect, and possibly how they reproduce http://www.mangasky.com/shingeki_no_kyojin_before_the_fall/4/34/