- Arc Fatigue : One of the major criticisms against the relay of the series is that the plot became more episodic and introduced spin-offs with more characters and sideplots (Kriss' redemption quest, a war against a Christian emperor, Louve's adventures, Aaricia's new boyfriend,...) while the main story is still unfinished. For instance Kahaniel's resurrection, announced in the 2007 book, only happens in 2013. And the following volume, The Scarlet Fire, was not published until November 2016.
- Ass Pull: In the second book focusing on Louve, we learned that Aaricia has a magical collar inherited from her mother. It had never been mentioned in the whole main series.
- Complete Monster:
- Shardar from The Fall of Brek Zarith is especially nasty, deciding that rather than just surrender his rule to the rightful heir to the throne, it's better to poison his own court and destroy all his treasures, leaving the kingdom bankrupt, hoping that, to restore it, the new ruler will be forced to become as big a tyrant as him, while he escapes and plans to start new conquest, using the psychic powers of the baby he kidnapped.
- Volsung of Nichor is a Dirty Coward introduced and killed in the third album of the series. In The Guardian of the Keys, he is brought back to life by evil lesser deity, Nidhogg, who turns him into a perfect doppleganger of Thorgal. The deal is simple - he will seduce another diety who happened to have a soft spot for Thorgal, the titular Guardian, steal her magic belt, and bring it to Nidhogg, who will return him to his real form and grant him new life. What does Volsung do? He steals the belt, returns to Midgard, kills Thorgal, takes his place, and, using magic powers of the belt, takes over the control of his village, murdering the current chief, rapes his wife, and threatens to smash the head of Thorgal's baby daughter, all to destroy Thorgal's good name and avenge his own death...that he had brought upon himself - Thorgal's only crime was being there when Volsung got himself killed, he hadn't move a finger to help it and couldn't have stop it in any way.
- Crack Pairing: Vigrid and the Key Guardian in the second album of Louve. Who would have ever thought?
- Fanon Discontinuity: The Kingdom under the Sands is by far the least popular album. Besides this, some fans think the series should have ended with the Qa story, the Shaigan story or when Van Hamme gave up the franchise.
- Foe Yay: Kriss shares lots of it with Aaricia (especially the bathroom scene in Kriss of Valnor).
- It has also summed up her relationship with Thorgal very well ever since the two met.
- Funny Moments: A young Jolan learns that his magic powers make him a god, and claims that his father has no power over him. Thorgal counters that he does have one power...
Jolan: Oh yeah? What can you do?
<Hauls Jolan over his knee and gives him a well-deserved spanking>
- Jerkass Woobie: Kriss. Imagine being in love with a married man whom you hate.
- Older Than They Think: Gandalf-the-mad's name is NOT taken from the Lord of the Rings character. Both characters take their name from a dwarf in the Poetic Edda.
- Padding: In "The Fall of Brek Zarith", a full page is just about Thorgal meeting a monster armed with a sword, fighting it and killing it. You know, just... for action.
- Rescued from the Scrappy Heap: Aaricia in the first few albums was nothing but a shallow damsel in distress and the mess in Three Ancients of the Realm of Aran resulted from a very stupid decision. The Fall of Brek Zarith gave her a strong characterization and finally she Took a Level in Badass in the Qa Story.
- Some Anvils Need to Be Dropped: The second book focusing on Kriss gets two: rape is bad, and so are pedophilia and incest.
- Tear Jerker:
- Kriss' backstory. It even makes FREYA cry.
- Varth's backstory and death may invoke Cry for the Devil for some.
- The Untwist: Taljar Sologhonn being Jolan.
- Woobie, Destroyer of Worlds: A very dark example with Ogotay (aka Varth, Thorgal's real father). On the one hand, he's a genocidal Evil Overlord who tries to take over the world. On the other hand, he's the only survivor of his space expedition trapped in a foreign world and he lost all his friends and his wife and child. He's been driven to utter madness well before Thorgal meets him.
Ogotay: "And you too, you will adore me, like the others, and you will obey me, like the others!"Thorgal: "I see no god. I only see an old man who thinks he's a god. An old man who's been driven mad by grief and loneliness, and who takes his revenge for his exile by spreading death and destruction.