Let's be real: most zombie stories aren't about the zombies, they're about people turning into monsters while they're still walking around. The emotional arc is usually a stripping away. You start with your normal person—a dad, a cashier, a student—clinging to their old self, their old rules. Then the world breaks down, and so do they, or they harden into something else. The real horror in something like 'The Walking Dead' isn't the gore; it's watching Rick Grimes slowly shed his sheriff's morality, piece by piece, until he's doing things his old self would have found unthinkable. That's the emotional evolution: not growth, but adaptation, and questioning whether what's left is even a person anymore.
I think the most interesting ones explore survivors' guilt, not just the fear of being bitten. Like in 'The Girl With All the Gifts', the emotional core is this twisted, loving connection formed in absolute horror. The evolution is learning to love something in a world that has no place for love anymore, which feels more profound than just becoming a badass with a crowbar.