* AudienceAlienatingPremise: These books might be a hard sell even to {{Xenofiction}} fans due to moles [[WhatMeasureIsANonCute lacking the widespread appeal of]] [[Literature/WarriorCats ca]][[Literature/TailchasersSong ts]], [[Literature/{{Survivors}} dogs]], [[Literature/WatershipDown rabbits]], [[Literature/TheSight wolves]], [[Literature/FireBringer deer]], [[Literature/WingsOfFire dra]][[Literature/AgeOfFire gons]], [[Literature/TheFirebringerTrilogy unicorns]], or [[Literature/TheSummerKingChronicles gryphons]].
* MoralEventHorizon: [[spoiler: Mandrake's]] aforementioned [[spoiler: killing of Rebecca's newborns.]]
** Later on, Rune will [[spoiler:kill Bracken's children, with the exception of Violet, and blame it all on Mandrake]].
* NightmareFuel: [[WhatDoYouMeanItsNotForKids 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 ''WesternAnimation/WatershipDown'' levels, by the way), infanticide, parental incest/rape, cannibalism (both out of necessity and pure evil), the [[BrownNote Dark Sound]], horrible depictions of plague, and so many deaths it's hard to count.
* TheWoobie: Many examples throughout the series, including Rebecca, Tryfan, Spindle, and even arguably, [[spoiler: Mandrake]].