Batman Begins is a Batman story through and through, but The Dark Knight is a Joker story about testing the ideals presented in Nolan’s first entry.
The Joker might be an over saturated movie villain due to Hot Topic and aggressive fetishization of his villainy, but guys, he’s really fucking evil. I mean, he’s constantly tossed into Best Villain lists but this one is well deserved. The Joker isn’t a man. He’s an uncontrollable vortex of chaos and destruction. A living embodiment of pure anarchy bringing down the established order Batman and Gotham PD are barely scrounging together in their fight against the mob.
None of that matters to the Joker. He only cares about Batman. He only exists because of Batman. He wins by Batman beating him. Every punch thrown, every second Bruce puts on the cape and cowl, The Joker inches him further into his labyrinth of insanity. He exists because Batman needs his other half. A living nightmare created by Bruce’s crusade against crime.
It’s a whirling ballet of a performance and characterization. Nolan and the late Heath Ledger bring to life a monster unlike anything cinema had ever seen, and likely will never see again.
And even in the face of the unhinged clown prince of terror, Nolan has crafted an optimistic story.
Every move the Joker makes against Batman, and by proxy the people of Gotham, the city enters a downward spiral. Gordon pulls a gun on Batman (why doesn’t anybody ever mention this moment, like, holy shit??). Bruce loses what he perceives as his avenue to personal happiness. Gotham’s white knight falls further than anyone. But the citizens of Gotham endure.
Symbols can be torn down, Monsters may live among us, but unified humanity can triumph even in the face of seemingly unstoppable horrors.