Alright, so I just finished binging this one last night, and I'm still turning it over in my head. The obvious, surface-level antagonist is definitely the serial killer that Detective Shaw is hunting—that's the 'devil' the title refers to, right? The guy leaves these ritualistic symbols and just seems to be a step ahead in this terrifying game of cat and mouse. But the more I read, the more I felt the story was quietly building up the police department, or maybe the whole system Shaw works for, as this secondary, more insidious kind of enemy. There's all that red tape, the pressure from the media, the shady past case that nobody wants reopened. Shaw can't trust his own partners completely, and that paranoia eats at him as much as the killer does. It's like the real 'devil' isn't just one person; it's the collective indifference and corruption that lets a monster walk among people unnoticed. The personal cost for Shaw is brutal—by the final act, you're wondering if beating the killer even matters when the machine that created the conditions for him is still perfectly intact.
That said, I saw a lot of debate online about whether the killer, Vasily, truly is the main antagonist or if it's Shaw's own deteriorating psyche. The chapters from Vasily's perspective are deliberately written to almost make sense in a twisted way, which complicates the usual hero-versus-villain dynamic. He's not just a force of evil; he's a product of something, and Shaw's obsession with understanding that maybe starts to mirror it. I don't think the story gives a clean answer, which is what I found so frustrating but also kind of brilliant. It leaves you questioning who the real monster is by the end, and whether that distinction even matters when the damage is done.