How I imagine the Secret History cast + character analysis below
The characters are bound together. The dynamic between the characters unfolds their descent into the worst versions of themselves.
Richard Papen: the narrator/protagonist. Infatuated by a group of enigmatic classics and Greek students, decides to throw all his chances of getting into this mysterious class.
Richard comes from an impoverished background, extremely detached from his parents and hardly nostalgic about his boring hometown in California.
It's not a secret that he's obsessive, his most famous quote is him admitting that his fatal flaw of character is a morbid longing for the picturesque.
I think it's the sin of greed that resonates with him the most. Throughout the book there are not so subtle hints at Richard's sadism and obsessions, from his apathy (sometimes) to having had abused a small animal in his childhood and his fantasies about raping Camilla Macaulay and Francis in a wheelchair, co dependant on him.
He was drawn to the Greek class because of the enigma and dechipherable air around them and admitted multiple times to have romanticized them. His romanticicized fantasies about the Greek class, in a way, is his way of attempting to have the upper hand of power over the narrative, which he fails at. Nonetheless, he has the most power over how the characters get represented and their stories are told through his carefully observant, but not unbiased lense, making him a rather unreliable narrator.
Bunny Corcoran: his friendship and later on his death, connects the Greek class together in a way that only one other character could rival. He's explicitly disabled (dyslexic, also sent to prestigious disability schools) and I speculate he may have a personality disorder as well.
Bunny is erratic, much co dependant, impulsive, has a cruel way with his words and recognizing others' insecurities and weaponizing them childishly.
Yet (some of us) can't help but be drawn to this chaotic character. Bunny, is a man of jealousy. As his character unravels, so does the contradictions in the seams of his personality and Richard's view of him.
Having been raised in a family who cares plenty about appearances and prestige, subtle implications of motherly neglect; Bunny grew up to be a very insecure man. It's precisely his jealousy and sensitivity to insecurity that allows him to stab others where it hurts the most. He's detached from the rest of the group in a sense; he seems the most erratic and moody yet he's the least capable of deluding himself to unrealities of himself.
Francis Abernathy: personal disclaimer: he looks the hottest of them all. Classic aesthetic and everything. I really really wanted to like him more than I did, the ramnents of the younger queer fujoshi in me was drawn to him, but the 23 yo me has to admit his character was rather unexplored and it's disappointing because he's the only explicitly gay character.
Francis comes from a wealthy background, old money style. His grandparents raised he and his mother both, as she'd bore him at a rather young age. Francis is concerned with appearances, highly anxious, perhaps a bit of a people pleaser too.
His deadly sin I believe, is lust. He's had "sex" with Charles multiple times when Charles was highly drunk, and Charles doesn't seem particularly fond of the experiences. I hate how homophobic this makes me sound but Francis is a rapist. The scene of him and Richard, consent was very obviously dubious, save the discussions about Richard's denial of his bisexuality.
Yet I believe his not-so-consensual sexual attitude is different from Richard's power fantasies. This is mostly speculation on my part. Having been born in a homophobic family, I believe there may be a deep sense of shame around his sexuality and the feeling of being "the odd one out", though he pushes that insecurity into subtly till we see his heightened anxiety around people he actually likes and his deep concerns about being disliked by them and disappointing them. This doesn't excuse his actions, but provides perspective into why he can't face Charles while sober, it's because of the shame he feels around his sexuality and desires.
Charles Macaulay: one of the twins, comes from a middle class background. Through the narrator we learn to see him as a pleasant, agreeable and kind hearted individual.
Yet throughout the progression of the book he becomes less and less like his agreeable self, that is due to his sin of gluttony, his severe alcohol addiction making him a stranger to everyone around him and even the closest to him, his twin sister Camilla.
Camilla Macaulay: I have more rant than I have analysis of her character. She's the woman of the twins and also the group and boy does she fulfill the role of a woman in the Iliad fashion and I mean that not as a compliment. We know Richard is infatuated by her enigmatic aura, she's a puzzle he can't unlock, he projects his darkest fantasies onto her.
I've seen theories about her being a femme fatale, a secret seductress bringing men to their ruin; which proves to me misogyny goes beyond just the intentional portrayal of her character through Richard's lense because she was a victim of Charles' domestic abuse on his alcoholic rampages and there is no indication whatsoever that she influenced any men of the group to do what they did except falling in love with a man. People want her to be a girlboss master manipulator so bad, but you wanna know the real bitch? It's Henry fucking Winter.
Henry Winter: last but not least, Henry Winter. He comes from a wealthy and elite background, rather detached from his family. He suffers from a canon disability (cluster headaches) and also implied mental ones; some theorize him to be autistic, some others theorize him to have had brain damage as implied by the accident he had as a child and the scar on his temple.
His potential mental disabilities are attributed to his detachment from the people around him, extreme obsessions that make him an incredibly capable person in multiple areas of life but limited in others, rendering him rather inflexible and he's often othered by those around him, often either romanticized and seen as hyper-capable or because of having an enigmatic, strange but charismatic personality.
Henry is a man of great pride, the Greek thought equivalent of which being Hubris. He moves through the world, making decisions about life and death how a divinity would. He selects who gets to be and who gets to be removed (quite literally) from the group.
Henry exists in the backdrop of every other character's bad decisions that are the catalyst for their inevitable fate; his method of manipulation is rather passive and much subtle. He brings out the worst in people by playing with their insecurities. The relationship the characters have with him are the catalyst for their actions, not the other way around.
Henry is the knot in the bundle who cuts loose threads masterfully.
Henry as the tragic hero theory: being the common point of contact with all other characters, I theorize that Henry is the actual protagonist and the tragic hero of this tragic story. What everyone has in common is Henry. Richard tells his story and once Henry steps out of the picture, the story ends.
Julian Morrow: Julian comes from a wealthy background, much similar to Francis and Henry. He has an enigmatic and extremely charismatic character, so superficial in his behavior that it's almost theatrical.
He's extremely and unreasonably selective about who gets in his class and his influence over his students extends beyond just the class. He's a benevolent dictator, as explained by Richard.
I believe his deadly sin is Sloth, he lives in an illusion he's created by very selectively choosing what he sees and what he does not, reflecting his deep sense of detachment not just from the people around him but also modernity.