User blog comment:MeDeoPal/On the Origin of Titans and Shifters/@comment-179280-20130823001810

Awesome theory. In fact, it gave me an idea on how the special Shifters came to be too. You see, the Colossal, Armored and Female titans look quite different from regular titans, and they may have been created as means of combating them. That would explain why they are attacked by regular titans. Ymir on the other side, got her Titan power when she stole it from the people who created the Titan Shifters. All of them failed to serve their purpose and roamed the land during decades before regaining conciousness again, though.