The demon and Klug shared more than they thought.
They both, for instance, had a love for books; while Klug liked science more and astrology, the demon had other preferences.
Among the creature's favorite things were; besides cakes and sweet stuff, were odd books about odd topics.
"Alice in Wonderland", "Grimm's Tales", and he held a big interest in comics.
Of course, Klug couldn't help but find the taste nice.
The book the demon was sealed in was, after all, entirely empty.
Well, empty, save for a disclaimer.
If you were sealed in an empty book, you'd like stories, too.