Yeah, it's just my guess. Void vs Titan. Could go either way. We don't know what exactly happened to the magic from the well after is blew up. She could have absorbed some of it, or it still could be present under the sea. All just guess work of course. If "energy cannot be destroyed" theory is also true for Azeroth, then the power has to have gone somewhere. What i'm saying is she could be wielding both powers at the moment.