Board Thread:Wiki/@comment-24930713-20150810223555/@comment-5774380-20150812144406

To me it's clear that it's Erwin. He even has been preparing scenarios of "what should you do when I'm dead".

On the other hand, it's very unlikely that any of the Big Four (Eren, Mikasa, Armin and Levi) will die; the first three because they are the protagonists and the series revolves around the realization of their dreams, the fourth because he is too damn popular.