So this isn’t really a new theory but it’s different so that I can include my new ship. I think Ozpin is the wizard and Salem the original winter maiden. I think that at first the four sister were given this “gift” by Oz, and they fought for his dreams and goals. But as the fighting became heavier (or perhaps they felt bad for killing these creatures instead of trying to save them?) the Spring, Summer, and Fall maidens decided they didn’t want this gift (or curse) anymore. Here’s where my ship comes in. I think Salem was in love with Oz. I think she believed she and her sisters were special to him too, after all why would he have given them such a power? And once the maidens began to grow weary of fighting the only reason why they stuck around was because Salem convinced them. Because she believed in the future the man she loved believed in. However, something happened, something big. Maybe the big dragon that reproduces grim came about and the sisters were able to maintain it or trap it somewhere (remember glynda seemed to know about this dragon being close by, she knew it was coming) but at a cost. The three sisters died and when Salem returned to Oz she realized that not only did Oz not care about the sisters dying, she found out that the powers were passed down to others. Others doomed to the same fate her sisters were. What’s worse was that Salem ENCOURAGED their deaths, her sisters wanted out but she convinced them to stay because she was blinded by love. This made her angry and bitter (because she sounds angry to me in the finale and how can she be angrier at Oz than by just losing her sisters? By playing a role in their deaths) and so she trained for years and used this anger to control rather than attract grimm (which shows why Cinder wouldn’t be attacked by that big dragon grimm and how maybe she created that ugly bug through the glove?) And now she’s just back to take revenge in Oz.