Though I Am an Inept Villainess: Tale of the Butterfly-Rat Body Swap in the Maiden Court (Light Novel) Vol. 1 by Satsuki Nakamura, Ei Ohitsuji (Illustrator)

In a kingdom inspired by historical China, five clans put forth their maidens as imperial consorts - but only one will be crowned empress. The frail and beautiful Kou Reirin, the so-called 'butterfly' of the imperial court, is a shoo-in to marry the crown prince. But when 'court rat' Shu Keigetsu lashes out at her during the glittering Lantern Festival, it's Reirin who wakes up in the dungeons! Body-swapped by her assailant to steal her position at court, Reirin's plight seems dire... to everyone else! Now that she's got a robust new body, not even the looming threat of execution can stop her!