What does the ending of Attack on Titan actually mean?

The ending only works if you accept that AoT was never a power fantasy — it's a tragedy about determinism and inherited hatred.

Eren is not presented as a mastermind. He's a traumatized kid with a god's power and a slave's mindset — 'a slave to freedom,' as the show literally names him. The Rumbling isn't a clever plan; it's what happens when someone who cannot accept unfreedom gets absolute power. He half-justifies it as protecting his friends, half-admits he simply wanted to do it, and the story refuses to clean that up for you.

The epilogue — Paradis eventually destroyed, war continuing, a boy finding the tree that resembles the one where it all began — is the thesis: violence doesn't end violence, it just resets the board. The one genuinely hopeful note is personal, not political: Mikasa's choice to love Eren and still stop him, and Armin's insistence on talking even when it's naive.

So the point isn't 'Eren was right' or 'Eren was wrong.' It's that the mechanisms of fear and hatred are bigger than any individual, and the story makes you complicit in wanting the Rumbling before showing you its cost.