I've done a few battles on Battle Chateau before. It's a great way to train your Pokémon, and, as said before, a decent way to earn yourself some money as well. (: I haven't been able to become a Duchess yet, but I'm on my way. The hardest opponent I have faced on the Chateau, so far, was Grant. His Auroras was quite defensive, and it's taken me nearly eight turns to have it defeated. His other Pokémon was Tyrantrum, which was pretty heavy on the offensive side of things. With only a single hit, it was able to take down my Blastoise… and it wasn't even critical. d: Usually, Blastoise could withstand about three to four attacks in a row. I have no idea how it's managed to defeat it with just one move, though.