* CompleteMonster:
** [[MorallyAmbiguousDoctorate Doctor Evazan]] ''murdered one of Zak's friends'' because he'd found that fresher corpses made zombies who were smarter and more useful. He then arranged for the resulting UndeadChild to bring Zak to him and injected him with the zombie serum and a poison that would make him go into a coma so deep, he'd be mistaken for dead and BuriedAlive.
** The BigBad of the first six books, Borborygmus Gog. All of the threats in those books are because of him and his suboordinates. He had a planet become alive and [[QuicksandSucks hungry]], and deliberately stocked it with a species that would make people feel welcome so they could be eaten, and then left it out to be discovered. He hired Doctor Evazam. He injected Tash with TheVirus while on the way to try and kill her uncle. He tested the [[IKnowWhatYouFear Nightmare Machine]] on random young amusement park visitors. He spent months posting stories about Jedi to the Holonet, which is so censored by the Empire that his is virtually the only source, to draw in and befriend people interested in Jedi, with the intent of making them agree to meet him so he can have their LifeEnergy siphoned - all in the hopes that one of them will be Force Sensitive so he can study it. And then there's Kiva.
* FridgeBrilliance: The DarthVaderClone thinks he's really Vader but is less scary and effective and more petulant than Darth Vader - ''like Anakin''. Which is another reason why Vader [[ThereCanBeOnlyOne hated him on sight]]! It's known from elsewhere in the ExpandedUniverse that he hates ''himself'' more than anything or anyone.
** FridgeLogic: Why didn't Yoda do anything about the Children? At the time it was written it was assumed that Yoda had been there for a very long time and would have seen the NoPartyLikeTheDonnerParty situation brewing and spilling over, it was happening within walking distance of where he lived and they ''saw him watching them''.
* GrowingTheBeard: For some, ''Army of Terror'', in which the series wrapped up the Project Starscream storyline and moved away from old formulas.
* NauseaFuel: ''The Planet Plague'''s BlobMonster [[spoiler: The Virus]] and Spore, especially.
* TooCoolToLive: Captain Hajj.
* WhatDoYouMeanItsForKids
* TheWoobie: Both Tash and Zak. They're twelve and thirteen and lost everything six months before the first book, when Alderaan was destroyed. Every time they pick up material possessions these end up getting lost along with whatever ship they currently have. [[OrphansOrdeal Their guardians are grudging]] at first, and keep dragging them across the galaxy into danger. Tash is weird and Force-Sensitive, which gets her blamed sometimes for things that aren't her fault, and has [[PleaseDontLeaveMe abandonment issues]]. She wants to withdraw and be away from everything but feels like she can't because [[PromotionToParent someone has to look out for Zak]]. Zak has BadDreams and misses their parents terribly.
** StoicWoobie: Hoole.