Lu Yin didn't think that there was anything wrong with what she had planned. Her father was Father Lei's bodyguard but died while saving Father Lei; ever since then, the Lei parents had promised her and her brother that they would treat the two siblings as their children.
However, when faced with a situation where they had to choose between the Lei siblings and their own children, they would of course choose their children. In the past, Lu Yin had nothing against it. She even acted sensible and told Aunt Lei that it was only right for her to pay more attention to Lei Yan.
But now the times have changed. The world had fallen and the man-eating monsters had started to run amok. Unlike Lei Yan, she didn't awaken as a supernatural being and had to rely on her brother, who awakened as a poison ability user.