The other comments really say what is needed here. Right now they feel like cardboard cutout villains to fill the 'burn the witch'. There is good drama potential with how they deal with heretic priests and the like. Go to Comment
It looks like a cook's book. It is a cook's book. It is also where the cook, who happened to be a master spy, encoded all his secrets and contacts. The book has innocently fallen into your group's hands. Everyone wants it, and many are not subtle or peaceful in their attempts.