As what mama Kelly mentioned before about Diana has an extraordinary destiny about her but there was never anything about baby Kelly. Kelly was the "hybrid" that nobody saw.
Everyone knows that Diana is the most powerful wesen (well except for the skull guy). But if by history and how the world of wesen is, Zauber/Hezenbeist are feared by all wesen and same as Grimms. So when you have a hybrid of both, technically you'd get the best of both worlds. Having both of them on the skull guy's side makes him unstopable.
So the final battle will be at the cabin.
Seriously who and how can this guy be stopped, no mortal wepon can do anything and Nick well, he's kinda useless really, I guess all wesen are. "Except" maybe Diana and Kelly.
Maybe Nick can possibly manifest a power from the stick?!
Hank and Wu dying! Damn didn't see that coming! As much as I would like them to survive, I hope they don't use to stick to resurect them, lets face it if that happens, no one will ever die! The interesting is that they are the only ones that were not "wesen/grimm" in the group amd I guess now Eve too. Wu was something different.