I Transmigrated into a Book to Help the Male Lead Cultivate, but Accidentally Became a Demon

Wu Yue wakes up one day to discover she has transmigrated into a book as Wu Yue, the vicious cannon-fodder female supporting character. The male lead is a crown prince whose kingdom was destroyed when he was twelve. He became a slave while fleeing, and the original Wu Yue later bought him and tormented him day after day. In the original story, Wu Yue is exceptionally cruel. After tormenting the male lead for two years, she has nearly tortured him to death and is about to drown him in a pond as fertilizer for her red lotus. As it happens, she transmigrates into the book at that very moment...