Disclaimer: The point of this post is not to trash "Destiny of the Wulf". It is to serve as an example of plot holes in general. A number of readers disagree with me and that's okay.
TvTropes defines "Plot Hole" as "gaps in a story where things happen without a logical reason". They can be deliberate or accidental but in both cases they can damage the Willing Suspension of Disbelief. These sorts of things include events that don't follow a logical cause-and-effect transition path, characters whose motives and actions don't make sense for their own characterization and worlds that don't work according to their own internal logic. If a work seeks to be taken seriously but has numerous plot holes than it will be mocked instead.
Tvtropes defines "Idiot Ball" as "A moment where a character's stupidity fuels an episode, or a small plot line."
It is a bout of temporary stupidity that is enforced upon a character by their writer so that the writer can direct the plot in the way they want. This trope is so commonly used and appears in so many ways that it has a long list of subtropes; from poor communication to forgetting about inconvenient superpowers to sudden relationship conflicts.
Idiot Balls are one of the things I look for when I review a book. I can't stand them because they damage the integrity of the book; the event is unnatural and so the events it spawns are unnatural and as a result I can't take them seriously. Characterization also suffers because it sets back development and turns them into plot props instead of true characters. If I don't see one of these, the worst I'll score your book is a C-.
This post will focus on last book I reviewed: Destiny of the Wulf by Harrison Davies. (You can read that review here) and the categories I will use are 1.) Bad Leadership, 2.) Because Destiny Says So. 3.) Bad Security and 4.) General idiocy.
WARNING! This list will cover the book from start to finish. If you don't want spoilers, do not read. I repeat. Cover-to-Cover spoilers await you further down this post.
1. The boys have this splendid destiny and yet they're raised in a small village without more protection than their parents. The Brotherhood knows how important these two are before they're born and their father is a high ranking member, yet he leaves the safety of the temple for this fishing village. There are many ways the boys could have died as a result of this decision. Then the Brotherhood would be without their pair of saviors before the story starts.
2. The Brotherhood's security is lacking. It relies on scary tactics and a single chasm that is enchanted to carry allies across but not enemies. There are no patrols or anything to monitor the chasm. For a bastion of good, there is surprisingly little stopping an invasion. This means it is easy for Draken to start one.
3. Draken is banned for life from the Brotherhood Temple and even after the boys insist he come with them (itself an idiot ball considering their relationship from previous chapters) he has a single person guarding him. This person pays little attention to him and is easily killed.
4. Merein, the former Curator, says there is no need for anyone to visit the Scroll of Life. Yet she shows Connin because she thinks he would find it interesting. This means disabling all the security measures to keep Death away for a moment's wonder. She admits that there is no way to stop Death if he ever got this far. This is like exposing one's heart to a dagger because it would be interesting.
5. Death possesses Connin. It's not explained how he does this (itself a plot hole) but what I'm focusing on here is that no step taken to make sure it doesn't happen again. This guy is one of the two leaders of the Brotherhood and one of the two saviors, yet the bad guy jumping into his mind doesn't worry anyone after the event.
6. The boys' village gets into famine trouble because beavers made a damn in their river. This by itself is a problem because couldn't they have located the problem earlier or found something else to eat?
7. As a result of the famine, the village makes a trade deal with an orc community to get by, and they don't keep up their end of the deal. This village believes the orcs to be savages and they lost men in the negations and yet they don't keep up their end of the bargain. This leads to an attack that kills most of the place, including the boy's parents and almost themselves.
8. General Jericho, decides to take a unnecessary risk because he's retiring soon and he wants a little extra glory. His home and way of life are on the line. It is unsurprising that he is captured as a result.
Because Destiny Said So
9. The boys are chosen for two of the three highest positions in the Brotherhood: Curator and General. There is no reason for this other than Because Destiny Says So. The current curator has been doing a great job so far so why doesn't she continue while the boys do their save the world thing.
10. If Destiny is going to say they have these roles then how about some battle plans or information on the locations of the Macguffins?
11. The Brotherhood at large believes that the boys' father left the Brotherhood to marry their mother. It later said that this is not the case but then why make that claim? It makes them antagonistic to the boys because of the Sins Of Our Fathers.
General Plot holes
12. After their parents are killed, the boys are raised by their evil uncle. He was a leader in a civil war that tried to take over the Brotherhood with dark magic. The other guy was thrown into a volcano but he was just banished. This is the guy that raised the two saviors. You'd think their parents would have a better role model waiting in the wing.
13. Because of their upbringing away from the Brotherhood, the boys dislike talk of destiny, detest the gods, lack training, and are thus unbelieving and uncooperative when they met the Brotherhood. If they were so destined to work for the gods then why don't their parents raise them this way? They tell the boys nothing when they were alive yet insist on it after they become Spirit Advisors.
14. The guide to the Brotherhood Temple (Trenobin) has one of the Swords of Cerathil (the ones mentioned in the blurb) and says that the others are lost and makes it sound like it's no big deal. "Sadly" isn't the word I'd use to describe something that would put the survival of the world in jeopardy.
15. Later on, Draken declares his intent to find the swords and says he needs the boys to help him do this. Trenobin acts like this is some terrible evil and declares that he's going to stop Draken. This is precisely what the boys need to do; find the swords. I can only assume that Trenobin was misinformed about what the swords are which is itself a plot hole because he's one that's supposed to use it for the world-saving-thing in five years.
16. The only thing worse is how Connin "defeats" Death. These two together come straight out of Harry Potter. It is not explained how submitting to Death allows one to expel Death from one's body. You'd think Death would be aware of something like that.
This book has some good world building, an interesting culture for the Brotherhood, and the makings of a great Order vs Chaos style struggle between the Brotherhood and its thus far nameless adversary. The boys themselves have this Brains and Brawns dynamic that worked well during a battle sequence. The problem are all these plotholes. They turn me off of future books in this series.