It feels like there is some story behind this, like the woman killing herslef in past with help of those cubes. At seasons we see that she is the shadow and the shadow kills her. Somehow I feel that this really has a backstory, that can't be just coincidence.
It looks like(time for a supposition of mine) everything started when she went to rusty lake. Somehow I think she went to rusty lake and discovered the power of those cubes, went back in time, killed herself in past and now it's a paradox that does everuthing to not to be discovered. I know, I know, that's probably just my craziness, but who knows. It may be truth.