Very interesting chapter. First your explaination of where the magic users were was good, logical and sad.
Harry's thought's upon learning about the past covered it rather well.
Having one of Luna's kin on hand with a letter from Moony no less was most heartening. It was both an excellent lift for a bit of a dishearening chapter and a nice little hook to keep one's interest in what is to come. (Not that it was required, I'm not about to pass on this - too interesting.)