User blog comment:NickFusi0n/A Theory on The Coordinate and The Wall Titans/@comment-200.83.222.106-20140611030035/@comment-95.180.66.192-20140613225118

I beleive all of the Reiss family are titan shifters, and all the titan shifters present (apart from ymir) are of the Reiss bloodline. Did you notice that every single one of the titan shifters has a unique ability? Reiner is completely armored, Bertolt is huge, Annie can focus her hardening and healing to a single spot. But when you look at Eren, he's just a regular titan. So maybe, just maybe, the special power of his Titan is the Coordinate ability. Anyway, i here's how i think it is:

-Every titan shifter alive is a Reiss (apart from Ymir). Titan shifter powers are transfered from parent to child. Grisha turned Eren into a titan with that injection, and then had Eren eat him, in order to transfer the Coordinate and Titan shifting power. A hundred years ago, when the walls were built, the Reiss family had used the Coordinate to force Wall titans/ Huge titan Shifters into the walls. This angered certain members of the Reiss family and they left the walls, and their descendants are Annie, Bertolt, Reiner, and their friend that was eaten by Ymir (and possibly some other Titan shifters that we haven't seen yet). Grisha was was the brother of Lod Reiss, and the previous Coordinate. Lod had plans of expanding his territory and building another wall using his brother's power. Grisha, however, didnt want to have anything to do with that, and ran into hiding to where the runaway titan shifters are. They had plans of overthrowing the current government, and liberate the people of the city from the walls. When Grisha left that time at the begining, he actually went to aid Reiner, Bertolt and Annie, by sending all the titans into the walls. He then gave his power to Eren, as it was needed to pass it on to the next generation. Lod is some super badass Titan shifter, which is why everyone else obeys him. He now plans to transfer Eren's coordinate ability to Historia, and use her to fulfill his grand plan of expansion. Why is he doing it? Why doesn't he simply eradicate the titans? Because he loves the power he holds over those stupid people! it's all in the lust for power!!!! The beast titan is like one of the first Titans, and they are the next stage of human evolution. And no he's not the only one of his kind, there are more beast titans out there.

I think my theory is crazier than yours, isn't it?