Black Wind Flag was a rare spatial type Divine Spirit Treasure. 
It can block attacks that don't have the power to tear through space. It is capable of summoning huge tornadoes and storms.  It can also create a black hole.
Three Kunwu Masters used it to seal Sacred Ancestor Yuan Cha on Kunwu Mountain. Later, Devil Ancestor Yuan Cha detonated it. Han Li seized its remains.
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