What struck me most wasn't necessarily the central trio, but how Booth Tarkington uses them as instruments for a larger societal autopsy. The 'magnificents,' of course, are George Amberson Minafer, his mother Isabel, and Eugene Morgan. George is the bratty heir whose defining trait is a profound, unshakeable belief in his own superiority and the permanence of the old world. Isabel is all gentle, fading Victorian grace, tragically caught between her stifling family loyalty and her rekindled love for Eugene. Eugene is the outsider, the self-made automobile industrialist who represents everything the Ambersons scorn: progress, new money, hustle.
But the real key, I'd argue, is Fanny Minafer, George's spinster aunt. She's the nervous, gossipy, financially precarious observer living in the Amberson attic, and her anxiety about status and security acts as this hyper-sensitive gauge for the family's decline. Her pettiness and desperation are pathetic but make the social commentary so much sharper. Lucy Morgan, Eugene's clear-sighted daughter, is the other crucial lens; she sees George for what he is, loves him despite it for a while, but ultimately won't sacrifice her own modern sensibility for his archaic pride. The characters aren't just people; they're embodiments of a world in violent transition, and their collisions are what make the novel's melancholy so potent.