Board Thread:Manga/@comment-5774380-20160908231942/@comment-27321453-20160913184251

Manuel de la Fuente wrote:

Ethan Harmicar123 wrote:

It was never confirmed until Chapter 70, for all we know he could've injected himself in wall rose The Titan serum creates mindless Titans. Zeke was not mindless when he was first seen. He was evidently a Shifter already, and a very experienced one since he was able to retain his ability to speech. Coupled with how we've never seen mindless Titans that looked like Harambe.

All the different looking Titans (Colossal, Female, Armored and Beast) turned out to be Shifters.