Yes, it was hard. I've been dreading this whole section of the story for so long, because it was really complicated. How to get Reggie there, not have it be deus ex machina, have a demon present so they would be able to learn something about their special knives and their powers, but have the demons attack Dean through the hatred of human beings of things they don't understand, not hurt Dean too much, but tie in the very beginning of this story, have Sam defend Dean and explode with rage that they were hurting him, but not go too far with it, create a strong emotional reason for Reggie telling the boys that he know... it was all quite complicated and delicate. I hope it all worked the way I tried to make it work.