Winnie was an Ancestral God and had insight into many future events.
She knew James would not die and would surely win the fight.
However, Melinda’s words made her doubt herself.
Melinda mentioned that James would die if she did not take action. If that came to pass, the humans would fail to survive the Fourth Calamity, and everything would cease to exist.
The Heavenly Path would collapse, the Twelfth Universe would fall, and everything that happened would be just like a dream.
However, Win