Regina, a purple haired beauty who was the 1st daughter and child of the emperor, succeeded to the throne after the assassination of her father, just until her little brother became of age.
While facing plenty of hardships, news about the depletion of government funds due to her maniac younger brother's behavior, and her fiancé having an affair, begin to spread...
In the end, she loses everything when her fiancé and a mysterious oculus commits treason. In her last moments, she turns back in time with the relic of the First Emperor with a wish.
In order to stop the main culprit, Regina declares that instead of painfully wasting away her life, she will become an even trashier person than her brother so that he could succeed to the throne, all while teaching him how to be competent.
[Online, this story is known to me as -I became the trash princess- but it is also listen down by other names, such as -Shes the sister of a maniac-, -shes the nerds sister-, and -망나니의 누님이시다-.]
DISCLAIMER: NOT MY STORY, IM JUST DESCRIBING WHATS HAPPENING IN THE MANHUA BUT IN WORDS.