Board Thread:Speculation House/@comment-27143816-20160215042739/@comment-8.23.154.5-20160616200425

I don't think this is solid evidence of a tragic past, however if you pay attention to Cinder's expression change in vol 3 episode 11 where she first confronts Ozpin, it sounds like she truly believes he is evil or something along those lines. I believe this suggests Cinder felt she was wronged in some way by Ozpin, his associates, or the powers that be in Remnant.