Right now, the most interesting faction for me is the church/royal family.
I mean, they know about the titans inside the wall, they probably know what titans are too and they probably know that they aren't the only humans alive.
Which means they are under attack and I wonder how they'll defend themselves. Will they create titans on their own, and is Eren one of them? What I'm saying is, a country that doesn't retaliate at some point, won't win a war.
But if Eren is their "weapon"-tech, they did a very poor job protecting it etc...so, doubtful.