This is really interesting. So, when Wendy was battling Ezel on that cave, she was able to destroy a Face while on Dragon Force Mode. However, on the recent episode, almost all -in fact all of them- of the mages who attacked a Face wasn't even able to make a dent on it. This includes mages like Kagura, Lyon, Jura etc.. What does it mean? Maybe Dragon Slaying Magic has a special effect that made it possible to destroy a face. Or maybe, Wendy in Dragon Force (or Dragon Force in general) is just too OP. If we consider the latter true, then, since Wendy is now able to enter Dragon Force when she wants, will she now be stronger than the Likes of Kagura, Lyon or Jura? I know that sounds too far a stretch, but that is what I just observed. Of course we have to factor in things like, how long can Wendy maintain Dragon Force? How much she has mastered it, and experience. Power doesn't always equal being Stronger (if that makes sense).