Though I am an Inept Villainess - Tale of the Butterfly-Rat Body Swap in the Maiden Court (Teen 13+) Volume 1

In the Kingdom of Ei, five clans put forth their maidens as imperial consorts—but only one will be crowned empress. Just when frail and beautiful “court butterfly” Kou Reirin seems poised to marry the crown prince, jealous “court rat” Shu Keigetsu steals her body! Reirin wakes up in the dungeons as the conspirator, and things look dire…or do they? Now that she’s got a robust new body, not even the looming threat of execution can stop her!