My take on the titans so far is that yes, humans obviously become titans. Connie didn't just see a titan that looked like his mom- it almost certainly was his mom, and the rest of the villagers became titans, and there's a connection between the villagers turning into titans and the ape-like titan. (This is supported by the fact that the villagers disappeared, their homes were destroyed from the inside out as if the people inside turned into titans, and suddenly there was an ape-titan giving the titans orders)
The latest chapter makes it clear that Ymir suffered the same fate as Connie's mom and the other villagers, she was a person that became a mindless titan. All we know is that Ymir wandered outside the wall for 60 years after turning into a titan. Since the wall was standing for 100 years, if Ymir only wandered outside as a titan for 60 years, the wall was built before she became a titan... So there's another mystery: Was the ape-titan responsible for turning Ymir into a titan, or is there some other explanation? And how did Ymir get outside the walls? Hell, after turning human again and regaining self-control, how did Ymir get inside the walls and join the military recruits?
I'm really confused wondering who exactly Reiner, Bertholdt, and Annie are working for.
This is almost starting to feel like the titan-shifters would willingly eradicate humans and mindless titans in order to create a society specifically for titan-shifters, kind've similar to the anime Shin Sekai Yori where the people with PK use their power to kill all the humans without PK, and create a new society.
Otherwise, the titan-shifters seem to have no long-term goal. They don't know why there are titans inside the walls, and they kidnapped Krista so she could tell them. SO.
Let's all just pray that next chapter Krista gives us a massive infodump explaining why there are titans in the walls, and who the mysterious 'king' in the inner wall is.
Maybe, just maybe, Reiner, Bertholdt and Annie are good guys, fighting to free humanity from the 'king' as well as the ape-titan. Since we know nothing about the king, the entire titan conspiracy could be traced back to the inside walls and the king. Odds are pretty good that the king is connected to whatever caused the titans to appear. Or even worse, the king could be 100 years old if he's a titan shifter, since Ymir was able to live 60 years as a titan without aging.
