Be honest – the first time you read Philosopher’s Stone you didn’t have the foggiest idea Quirinus Quirrell was the bad guy. And hey, we were all duped. How could this meek, taciturn teacher be in league with the most dangerous Dark wizard of all time?

Re-reading the book for the second time (or third, or tenth, or thirtieth; there’s no judgment here), it becomes ever more apparent all is not what it seems with the jittery professor. The clues were all there. Let’s look back at some of the more obvious ones…

He faints because of the troll on Hallowe’en

Okay, so trolls are scary. That’s kind of their thing, being giant, lumbering man-eaters and all. But isn’t our man Quirinus supposed to be a bit of a dab hand at the Dark Arts? A professor, no less? Plus, we know he’d taken a wizarding gap year, charging around Europe and getting into mischief with hags. Why would a common-or-garden-variety troll cause him to pass out in terror? Unless (gasp!) Quirrell was up to something else…

Stammer, or something else on his mind?

Quirrell’s stammer is the most obvious indicator of his nervous nature. But it soon stops when Harry discovers his true intentions.

Is Quirrell so overwhelmed being tethered to Voldemort that he is prone to bouts of stammering? Is his stammer entirely a convenient cover story? Or does he have a competing (and probably distracting voice) in his head, throwing him off? We can’t quite be sure, but he certainly has a lot on his mind.

And what’s with his name?

In the literary universe of Harry Potter nothing occurs by accident, least of all names. That’s why the name of its titular boy wizard so perfectly evokes both an everyman and a heroic name fit for a king.

J.K. Rowling notes that Quirrell’s name was very close to ‘squirrel’. But his forename ‘Quirinus’ has somewhat darker overtones: it references a half-forgotten Roman god closely associated with violence and war.

Harry’s scar hurts when he looks at Quirrell

From Harry’s first moments in the Great Hall we’re led to believe Snape is the bad guy. But wake up, people; that early on in any book, if the author wants you to think somebody is the bad guy they’re maybe not the bad guy. Fair enough for not picking up on it the first time, but still: imagine Voldemort’s ugly mug, twisted with rage beneath that turban, staring straight at young Potter from the back of Quirrell’s head. Shudder.

He’s such a lousy teacher

If you’re going to teach Defence Against the Dark Arts you’d better have a damn good zombie story to impress the kids on day one. Certainly, that is, if you claim your turban was a gift from an African prince grateful for your supposed heroic dispatching of the undead. If you’re changing the subject and turning pink at this early stage of the game, alarm bells should be ringing.

That time he was ‘just passing’

When Harry and Ron, on their first day, indeed, were caught trying to force open a door to a forbidden corridor, caretaker Argus Filch threatened to lock them in a dungeon. Well, who’d have thought it: bashful old Prof Quirrell just happened to be in that same part of the building to save the day. Clearly not snooping on them. Oh no.

THAT overheard conversation

One week before exams, Harry earwigs on Quirrell sobbing, ‘No – no – not again, please… All right – all right…’ And fair enough, unable to actually see anything, Harry assumes it’s Snape delivering a stern dressing-down, as we’d seen a couple of times in the book up to this point.

But in terms of literary devices... if you don’t actually ‘see’ what’s happening, then there’s more going on than meets the eye. Or ear. Or whatever.

Harry literally dreams about Quirrell’s turban

In the dream, young Harry is wearing that purple turban. It talks to him, telling him in no uncertain terms to transfer to Slytherin as it was his ‘destiny’. Bit of a giveaway there.