Horizon Zero Dawn Explained: What Does The Ending Really Mean?

4. Aloy's Role & The Nature Of Determinism

Onto Aloy, whose existence comes from this war between GAIA and HADES.

At some point just before the events of the game, HADES is activated by the 'unknown signal', which causes it to begin the 'destruction of Earth' cycle, despite GAIA making some pretty good progress, both with machine life and the ecosystem itself (humans are flourishing in villages and cities, after all).

HADES' rogue activation systematically starts shutting down and wiping out all the other A.I. cores GAIA controls, until she too, is on the verge of being taken over. Instead of letting that happen, GAIA uses the birthing chambers inside the Cradle Facility to 'design' Aloy as a perfect clone of her creator, Elizabeth Sobeck, before self-destructing and shutting down to save the world from destruction.

GAIA's actions stop HADES' infection and render it inert, but her biggest gamble is in pre-cognitively assuming/knowing Aloy will follow the exact path that will reactivate her systems and defeat/restore HADES original parameters.

She 'knows' Aloy will be the first person to have full access to humankind's real history, and - thanks to the traits inherited from her 'mother'/Sobeck - will use them to access and restore the APOLLO program, allowing GAIA to continue watching over Earth with HADES back in his box.

Aloy's role is one giant comment on biological determinism (the theory that everything we're capable of is predetermined based on genetics), and in Horizon, this theory becomes reality, despite Aloy herself having an initially violent reaction to her whole life being pre-thought out.

Think about it: Would you find peace and solace knowing you're 'in your place', or is that an incredibly depressing thought?