The Proving is a tournament held in Mother's Heart for the Nora tribe that tests an adolescent's balance of swiftness and strength against enemies. Those who finish the Proving are awarded the status of Brave, and the winner is allowed to ask anything of the Matriarchs.
A contestant must survive an encounter with a herd of machines, kill one and take a part of it as a trophy, then traverse a trail while racing against other contestants, all while on top of a snowy mountain. The goal of the Proving is to simply make it to the end, but the boon given to the winner is incentive to be first to finish. The Proving is obviously a dangerous event, which mentions of deaths occurring, and dangers include being killed by machines and falling off the mountain.
In Horizon Zero Dawn, Aloy trains for and runs in the Proving with the intention of winning, in order to ask the High Matriarchs about her origins. The Proving Massacre is the catalyst for the events in Horizon Zero Dawn.
In Horizon Zero Dawn, a young Aloy decides to train for the Proving in order to learn where she came from. Rost trains her from an early age, until she turns nineteen and is allowed back into the tribe.
After arriving in Mother's Heart, Aloy takes part in the Blessing ceremony, then goes into the Hunter's Lodge to rest. She is insulted first by Resh and then by Bast for being an Outcast, and is only defended by Vala.
The next morning, all the aspirants journey up the mountain where Resh is waiting to proctor the beginning. The competition begins when a herd of Grazers come running towards them; the competitors are required to kill a Grazer and collect a trophy from the body. Aloy successfully kills and collects one, but the trophy is shot out of her hands by Bast. Aloy then loots a second trophy, but she falls behind as most other competitors have already gotten on the Brave Trail. Dead last by the time she gets to the start of the trail, she decides to traverse the dangerous old trail instead as a shortcut. The old proctor warns her that two died on the trail the previous year, but nonetheless Aloy manages to traverse it, getting ahead of the others at the last stretch. She plants her trophy at the finish line first, followed by Bast and Vala.
Bast tries to disqualify Aloy as she used a different path, but the proctor declares her winner and a Brave nonetheless. However, Aloy's victory is cut short when the Proctor is shot dead and the attackers begin killing the others.
Many contestants are known to have started training years before running in the Proving. Bast claims to have spent his whole life training (though that might have been an exaggeration) and Aloy herself began when she was about six years old. The specifics of training for Nora tribe members are uncertain, but in all likelihood it would have been similar to how Rost trained Aloy. Aloy trained in taking down machines, traversing steep mountainsides, running and jumping across large distances, swimming, and other activities to ready her specifically for the Proving.
The Blessing Ceremony
The night before the Proving, a ritual is performed in Mother's Heart by the High Matriarchs to bless the Proving. Each aspirant kneels before a lantern made by their mother (or in Aloy's case, Teersa) and lights the lantern in honor of her. For Aloy, she can choose to light the lantern in honor of Rost, her unknown mother, or herself. The aspirants then lift up the lanterns as they float in the sky while the High Matriarchs bless the ceremony.
The aspirants then spend the night together in a lodge, and are presumably led to the Proving site early the next morning.
Running the Proving
The Proving is run atop a snowy mountain pass. The contestants must climb the mountainside to where the Proving actually begins. The first task is to kill a machine and take a part from its body as a trophy. The contestant must then run to the Brave trail, where they race against the others to reach the end of the trail first. The first contestant who plants their trophy at the finish line is the winner. All contestants who make it to the end and place their trophies on the altar are made Braves, but the winner is additionally given a boon, which is anything they can ask of the Matriarchs.
All parts of the tournament are overseen by proctors, to see that the contestants continue the trail and to ensure there is no foul play. There are few rules, if any. For instance, Resh does not penalize Bast when he destroys Aloy's first trophy. Aloy's use of a shortcut was also permitted, although not recommended as she took an old trail that was falling apart and resulted in the death of two people the previous year. The proctors mainly appear to be present to make sure the contestants finish the run and decide who is the winner.
- Aloy is the only known outcast to run the Proving, let alone take first place.