Even Katara is pretty mystified about the Overlord. It went from just observing a crazed jabbering book to a person who's impressions and thoughts she cares about. Because of who the Overlord is, she won't admit that what he says does matter (even as a lecher) but she actually does care about him

And though she'll never admit it, she will be trying to find a way to not make him a book.