- Alternate Character Interpretation: Dee uses this to get Josh on his side; is Flamel their friend or a crook who keeps putting them in danger?
- Base-Breaking Character: Josh is either disliked by people who find him jealous and immature. Or else people sympathise with his status as The Un-Favourite.
- Ensemble Dark Horse:
- Scathach is one of the favourites out of the main cast. She also appears to be Michael Scott's favourite character; she's usually the one he talks about the most.
- William Shakespeare, given that one of the most famous playwrights in history is now also a Badass Bookworm and Gentleman Snarker.
- The Morrigan was featured prominently only in the first book and had less and less to do in others - but she is a fan-favourite of the villains.
- Virginia Dare, given that she establishes herself as a Memetic Badass within her first few appearances.
- Fridge Brilliance: Scathach fighting alongside Joan of Arc in the 100 Year War. She's Irish so of course she'd side with the army against the English.
- Genius Bonus: Quite a few of them, given the amount of historical and mythological figures involved. The passwords Machiavelli gives to his various security devices are an example; they're the original Italian titles of his works. Additionally it's now known that Machiavelli's famous The Prince was a joke and the portrayal of him as an Anti-Villain who eventually makes a HeelFace Turn reflects the changing public opinion towards him.
- Les Yay - Often times it seemed like he was putting more oomph! behind Scatty and Joan than Joan and Saint-Germain. Granted, their moments were there [Especially in Necromancer] but other times, it seemed the only thing giving credence to the couple were other people squeeing over the fact that they were finally married. Though it might just be that Scathach comes across as slashy with most women.
- Magnificent Bastard: Dr John Dee is the Big Bad of the series and although he's declared an outlaw by his masters at the end of the third book, he is not caught by them until the beginning of the last.
- Nightmare Fuel:
- The descriptions of many of the monsters qualifies.
- Abraham the Mage's fate of turning to solid gold, while remaining conscious for most of it.
- Perenelle wakes up to find herself in Alcatraz, trapped on an island with all sorts of monsters. And then even more in the sea to keep her there.
- The Reveal in the final book. Josh and Sophie discover that their parents are Earthlords, who took them from their real families and raised them to one day bring the rest of their kind back. Once they go One-Winged Angel, the description of their true form is quite horrifying.
- One-Scene Wonder: The Witch of Endor, but you can call her 'Dora', only appears in the last part of the first book (save for a brief appearance in the fifth) - with everything else about her being given to us second-hand or through flashback. Yet she is incredibly memorable.
- Paranoia Fuel: Josh and Sophie's parents turn out to be Osiris and Isis, ancient Earthlords. They stole both children from their real families and raised them to be awakened and use the power to resurrect the rest of the Earthlords. Imagine discovering that your parents - the people who it should be easiest to trust - have raised you to such a degree.
- Relationship Writing Fumble:
- If Scatty wasn't such a Shipper on Deck for Joan and Francis, you'd think she was into Joan herself. But it doesn't help that Scatty comes across as slashy with most of the other females in the story.
- Although the protagonists of the story are twins, sometimes their moments are written as if they were for lovers. It's always Sophie who convinces Josh to not go through with a FaceHeel Turn, and his devotion to her is like that of a lover. The last book reveals they're not actually related, making this a little better.
- Rewatch Bonus:
- Rereading the first couple of books with the knowledge that Aunt Agnes is really Tsagaglalal. Her overprotectiveness and nagging tendencies make a lot of sense now.
- Scatty instantly clicking with Sophie and bonding with her can take on new light when you hear that she's estranged from her own twin sister.
YMMV / The Secrets of the Immortal Nicholas Flamel