Okay... suspense, major plot twists... is she named? You said who she is is a major plot twist, so is her identity different or do you simply not identify her?
I'd suggest doing something where it's just a short scene. Short means the reader doesn't have time to get impatient but it does make them wonder "Who is this person and why on earth do we keep getting glimpses through her eyes?" Enough to make them want to know, without actually telling them anything.
I attempted to use this technique (poorly) in The Gatekeeper's secret where half way through the book I started incorporating excerpt from the Gatekeeper's journal. At this point you still didn't know anything about who the Gatekeeper was, and by the time you found out you were on the last journal entry. It just referenced similar locations, monsters, and circumstances.
An example: (remember, I did a bad job of this, but the concept is sound.)
Quote:
To begin at the beginning. The old one turned over a fresh sheet of paper and dipped his pen in the crude ink he made from the bloodstained river. The beginning was Dylann, Dylann as it had once been, clean and bright and beautiful. The crystal forests grew all over the cavern, their light shining on the underground dwellers. The river carried nutrients that allowed strange plants to grow on its banks and fish to grow in its deeps supported life. People flowed in to Kaverna, the great center of the strange land. Traders came from the southern gates, from Lannah, from Sadin, from Selvor’s Land. Once or twice they had a visitor through the Avar Gate, or the Mishkal Gate. The Cordez Gate was unopened. So was the Gateway to the Unknown.
Ah, that fated gateway! Behind it lurked all manner of evil things that no one had seen and no one wished to see. A spell of protection had been placed over it; it could not be breached by anyone on the inside. It could only be opened by someone who came through Dylann. Therefore it was watched, day and night by the most faithful of the Keepers.
Tears flowed from the eyes of the old one as he wrote. He had belonged to that order, the highest in Dylann’s society. He had been the one to betray it at the end.
The other thing, in this case, is that it's ancient history, where yours will be present day events.
It's similar to a technique I've seen in movies and television where you have your MCs walking down a corridor and then you'll have a shot from the monster or villain's POV. You don't see monster or villain, you see through their eyes. So you don't know what it is, you just know that something is there. That's what I'm guessing you want to do.
I'm beginning to gather you have an incredibly complex novel, and this will just add one more layer of depth to it.
(I really look forward to the day you let us read it!
) Hope that helped!
Most of my scenes will be short, as a matter of fact, so I'm glad to see somebody affirm that that's what needs to be done.
I agree with Vanya, but I reckon incorporate enough knowledge of how important she is to the plot. I mean, not making her seem less important than she is, but really important and showing her occupation, location, etc. just hiding that defining identity by a hair's breadth. I think it'd be this implied and definate importance that would be the major factor in holding the reader's attention. 