I was once the purest fairy spirit in the Nine Heavens, Yun Miao, and I was infatuated with the cold and noble Emperor Cang Yao for three hundred years, until he personally pushed me off the Immortal Stage, just to achieve his ruthless path.
The immortal bones were all broken and the soul was about to be destroyed, but I was "saved" by his eternal enemy - Demon Lord Xuanyan.
He reshaped me, using demon energy as bones and hatred as blood, and forged me into the sharpest blade, named "Youyue".
When I met him again in my demon body on the battlefield between immortals and demons, my sword pointed directly at the people he had protected.
Cang Yao, you see clearly.
Now that you are back, what will break your heart and overthrow your throne is exactly what you gave up with your own hands back then - the calamity.