These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
But lest us remember this was an act planned by his adviser, Rune. Later on, Rune will kill Bracken's children, with the exception of Violet, and blame it all on Mandrake.
Nightmare Fuel: Woe are the youngsters that get attracted to this book by the promise of cute moles, for this is what await them inside: gory violence(in Watership Down levels, by the way), infanticide, incest, cannibalism(both out of necessity and pure evil), the Dark Sound, horrible depictions of plague, and so many deaths it's hard to count.