Sorcery!/YMMV

Anticlimax Boss - In The Crown of Kings, the concluding book, you reach the Archmage of Mampang, the character hyped as the Big Bad since the introduction to book 1... who decides to turn into a netherworld demon (and the book is so unclear some readers thought the Archmage had died for no apparent reason). Said Demon can be killed instantly if you're playing as a wizard, and even if you're a warrior it only has a SKILL of 7 and a STAMINA of 7 -- being only partly-formed. Still, if you fail to beat it within five attack rounds you're dead. Given you only do two points damage a round most times that leaves little margin for error. It is still quite an anticlimax.
- It crosses into Fridge Brilliance if you realize that the Archmage has fallen victim to his own Bond Villain Stupidity. He intends to trick you into entering his prison tower, but if you confront him as Farren Whyde he doesn't have his badass wizard body to fight you with so he has to assume his demonic form. Basically, you've caught him at a distinct disadvantage and assuming his true demonic form is the only way he can fight back. Too bad that form is extremely vulnerable before it can fully transform...
- Also the Sun Serpent, who has been turned into a Sealed Evil in a Can offscreen.
High Octane Nightmare Fuel - The pitch-black chamber with swords poking out of the floor, the monster with heat vision that burnt your arm off if you did the wrong thing, the super-fast ram made out of solid marble that charged at you endlessly whilst you were in a locked room with it, the god-headed hydra...
That One Boss - That damn Manticore! Not to mention the Serpents...
- If I remember correctly, the Time Serpent was invincible unless you had the spell on the Goblin scroll.
That One Level - The maze in the end of the first book. Let's hope you didn't call for your goddess yet... and heaven help you if you brought along that damn Minimite.
- Also, the sewers in the second book. Another maze with difficult monsters, except that it's completely pointless. Luckily, it's also missable.
The Woobie: Captain Cartoum risks his own life to help you if you give him the locket with a picture of his Lost Lenore in it, and you then leave him "pining for his lost sweetheart".