User blog comment:Licht and Lux/Marco is not Dead Theory... A New One/@comment-26451068-20150522014953

At one point I did briefly consider the possibility that, in a plot twist no one saw coming, it might be revealed that the Beast Titan was Marco, and that he was part of Annie, Reiner, and Bertolt's group. But it's not a theory I expect to come true. Marco is most definitely dead.