I came to the realization that my novel series can be broken up into two arcs. The first being the Identity arc and the second being the Destiny arc.
The second half of the series is also a massive departure in terms of story structure and pacing. While Books 2 and 3 were written with an outline, it was very open and light. Books 4 through 6 I actually spent a month writing each outline and used music to help plot out each novel.
I wrote down what I visualized from the songs and put those writings into the outlines. This made the novels far more structured and focused. The series also begins to move away from the established norms from the first half, even more so then even in Book 3.
The series changes, and a new path opens.