This series is spectacular. I first read it in April in about 24 hours, and have been waiting with bated breath for the next installment ever since. Born of Aether lived up to and surpassed my expectations. It certainly wasn't what I was anticipating; it was better.
Akiko's story is the most mysterious out of the four. What with her isolation over the summer and laconic speech, we knew almost nothing about her until now. But whatever you were expecting, I can almost guarantee it wasn't this.
This series is amazing. Good luck, and happy reading!