User blog comment:Miskos3/Chapter 56, Review/@comment-29813281-20140407183845

I Actually wonder about "That" woman who was with Captain Ackerman. Eren looked angry when she appeared in front of them.

Indeed, there's relation between Levi and that man called Ackerman. Levi lived in the underground city below the capital, right? When Levi joined the Survey Corps, Levi disappointed him, as he said "It's my responsibility that this has happened."

I think they will try to kill Erwin in the next chapter. Perhaps, Eren will remember more the mysterious woman or she might appear.