Battle for the Spire
In order to wipe out all life on Earth, HADES facilitated an invasion of Meridian to reach the Spire. A group of Nora Braves and the Oseram Vanguard mounted a defense, but were overwhelmed by corrupted machines. The three warriors who could still fight gathered their forces, and were joined by Aloy just before going over the top.
The following fight was a race against time, with HADES unleashing wave after wave of corrupted machines. Eventually, with the destruction of the Deathbringer guarding the AI, the tides turned for the battle, and Aloy neutralized HADES, preventing a second mass extinction.
Tribal outsiders are traditionally restricted from accessing the Alight, but Sun-King Avad allowed Aloy and her allies onto the sacred ground due to the extreme circumstances of HADES' threat to Meridian.