How did a demonic witch become the leader of the righteous path?

Yu Zhao transmigrated! Good news: She transmigrated, and became a fair-skinned, beautiful woman with long legs! Bad news: She was taken in by a demonic cultivator as his food supply. There was nothing she could do but tearfully send her master to his death. Youth has no price, and her master melts in her mouth. Years later, her junior sister looked at Yu Zhao, dressed in green, sitting high on a throne, receiving the worship of thousands. She was utterly bewildered and asked, "Senior Sister, I just can't understand how a demonic demoness like you became the leader of the righteous path?" Yu Zhao smiled calmly, a halo of golden merit condensing behind her head flashing. "Junior Sister, look at me like this. Who would believe I was once a demonic cultivator?" Junior Sister: "..." This world has truly gone mad.