Let's break this down.

The first blank describes what's happening to historical novels - the "fragmenting of traditional historical narratives" suggests that older, single-perspective histories are being replaced or supplemented.
- A. want $\rightarrow$ "want" as a noun means "lack." If there's a lack of historical novels, that wouldn't fit the idea that new voices are emerging.
- B. rash $\rightarrow$ "rash" as a noun means "a large number of occurrences in a short period" - a "rash of historical novels" makes sense: a sudden increase.
- C. void $\rightarrow$ "void" means "emptiness" - opposite of increase, so no.

So first blank = B. rash.

Second blank: "many authors have _______ the opportunity to turn a light toward some of the darker corners of the past."
- D. forsaken $\rightarrow$ means "abandoned" - doesn't fit, because they're using the opportunity, not abandoning it.
- E. misapprehended $\rightarrow$ means "misunderstood" - doesn't fit the positive action of illuminating the past.
- F. recognized $\rightarrow$ means "seen and taken advantage of" - fits perfectly.

So second blank = F. recognized.

Final answer:
B, F