- Anticlimax Boss: The Archchancellor's hat. It takes over the Grand Vizier and a big show is made of his ability to effortlessly annihilate even the sourcery-empowered wizards. He's engaging in open warfare with Coin... and then Carding essentially trips him (although that's only made possible because he was distracted by The Luggage in the first place), causing him to lose control of the magic he was using and annihilate himself. Considering how much effort went into stealing the hat, transporting the hat, recovering the hat, etc, you'd think that more time would go into stopping him when it's revealed that he's Knight Templar willing to end the rule of sourcery by force, even if it destroys the world in the process.
- Complete Monster: Ipslore the Red is the eighth son of an eighth son and a wizard formerly under the Unseen University, before being thrown out for breaking the rule against marrying or fathering children. Though starting the prologue with the redeeming quality of loving his wife, he is still shown to regard his eighth son Coin, a Sourcerer—a wizard who can use magic without having to learn spells and can allow other wizards to do the same—as merely a tool for revenge and exploits Death by threatening to indirectly kill the boy should Death remove him from Coin's staff. Over the next ten years, Ipslore molds Coin into an obedient killing servant through Electric Torture and by making him dependent on his staff to prolong his revenge, in the process abandoning the love of his wife and losing his sole redeeming trait. In the main story, Ipslore has Coin murder several wizards to bring the Unseen University into line, including a wizard who was kind to the young child, then lets the university loose against the city by turning Lord Vetinari into a lizard—also threatening his pet terrier—and letting the wizards terrorize the helpless population of Ankh-Morpork. Under Ipslore's rule, anyone who attempts to interfere is killed regardless of their inability to stop Coin, a fate that almost befalls Rincewind. Eventually letting his hubris overtake him, Ipslore has Coin freeze the Discworld pantheon, with no care about causing The End of the World as We Know It from the Ice Giants arising or the Things from the Dungeon Dimensions exploiting reality's collapse.
- Hilarious in Hindsight: The Archchancellor's Hat can now seem like a dark parody of Hogwarts' Sorting Hat, even though this book came first.
- Inferred Holocaust: A huge number of implied fatalities, though there is debate as to whether the Reset Button covers these or not. One could say that a reason why the wizards change from amoral Vancians to magical Oxonians is that Coin/Ipslore killed all of the former.
- Moral Event Horizon: Ipslore takes a step over the line through his torture of Coin alone, but then really goes over-the-top with his subsequent takeover of the university and Ankh-Morpork, crushing anyone that has the misfortune of being nearby.
- Nightmare Fuel:
- After a few books of being generally harmless to the outside world (if far from it towards their colleagues), this book shows just what would happen if the then-amoral wizards got their hands on a major source of power - they waste no time terrorising the nonmagical Ankh-Morporkians, killing several and scaring even more away. To make matters worse, while future Archchancellor Ridcully genuinely had nothing to do with the incident, it's implied most of the senior faculty of later books (bar Ponder, who was too young, and the Librarian who actively fought against the Sourcerer) were involved in some capacity, though they at least have the decency to feel ashamed about it and downplay their roles (which was implied to be minor at most).
- The fact that by the end, the world is about to end because of both the Ice Giants and the previously-seen Things from the Dungeon Dimensions.
- The Woobie: Poor Coin's entire reason for being is to serve as his father's world-conquerer-by-proxy, and really wants nothing more than to be a good kid. Just try not to feel sorry for him when Ipslore encourages him.
YMMV / Sourcery