User blog comment:Xilinoc/Ch. 532 Everything but the Rain - The White Noise/@comment-5198194-20130404020021/@comment-7785845-20130404041116

Another possibility is that Masaki was simply out of practice when she was killed. Judging from previous chapters, she doesn't seem to keen on the whole fighting thing. So it could very well be that she gave up training and fighting to settle down and live a peaceful life as a normal girl, start a family and all that.