Houve uma pergunta sobre o propósito do Night Kings e uma das respostas continha informações que você poderia achar úteis. Ele disse algo como:
The White Walkers were created centuries ago before the long night by the Children of the Forest as a weapon to fight back the first men as can be seen in the TV show.
After the White Walkers were created both men and Children of the Forest had to fight them. They both made an alliance and were able to defeat the White Walkers (the Azor Ahai legend is from this period of time). After this, they built the wall and for some time the Children of the Forest even provided the Night Watch with Dragon Glass in the case of the Walkers came back.
A partir disso, foi apontado que a mágica que criou o White Walkers não funcionou como planejado , então eles tiveram que se unir e lutar contra eles.