User blog comment:San&Ashitaka/TITAN THEORIES/@comment-24056601-20131016031527

You guys think about this you know human beings and their tendencies to try and improve our ways of living and make life easier for us, lets imagine there was a deadly disease that infected the human world and it cause severe damage to the victims body making them lose their limbs scientist might have thaught that they could try and make humans survive this epidemic by having the ability to regenerate their lost limbs and any other parts of their body.

Ofcourse they got the drug went to a village that was infected tested it out on all the people, yeah for days it worked people were healed but after sometimes the "Titan power" took over and they transformed into mindless beast before humans realized what had happened they had already given the drug to 69 percent of man kind.

So the remaining humans took shelter under the walls the scientist made by the titans power to harden. The church probably got involved because they help spread the news of the drug.

Just a wild thing going on in my head but it still doesn't cover the fact humans can turn to titans maybe "special" humans regained their senses and got control of the Titan