Because the show’s extremely 1st episode. They destroy Guys and bears and in some cases dragons and turn them into ice zombies that join the ranks in their Military. But it really’s hardly ever been crystal clear exactly what the White Walkers, or their chief the Night King, basically https://liantong.com.tw/%e6%a1%83%e5%9c%92%e6%88%bf%e5%b1%8b%e4%ba%8c%e8%83%8e%e8%b2%b8%e6%ac%be%e7%94%b3%e8%ab%8b%e6%b5%81%e7%a8%8b%e8%88%87%e5%b8%b8%e8%a6%8b%e5%95%8f%e9%a1%8c/