I recently received my author copies of the Japanese edition of Dragon Moon. The Japanese covers for the Dragonkeeper series are all lovely. You can see the Dragon Moon cover here.
There are also black and white drawings inside the books—some at the beginning, and a small drawing at the beginning of each chapter, each one different and relevant to the chapter. They are really lovely, but I don’t even know the name of the illustrator.
Here are some examples from Dragon Moon.