Why Does Everyone in the World of Cultivation Have Inner Demons?

Xu Ruo was a helpless orphan wandering the world. When he was about to die, he was picked up by a rag and a man, and he began his journey of cultivation. As things develop, she discovers that the beloved elder brother has inner demons, the cold-hearted master has inner demons, and even her idol has inner demons. But something doesn't seem right, and the real demon is herself.