Though I Am an Inept Villainess: Tale of the Butterfly-Rat Body Swap in the Maiden Court (Light Novel) Vol. 9

After staving off sabotage during the Congee Conferment Rite, Kou Reirin and Shu Keigetsu have successfully turned the tables on the emperor's assassin. Their former adversary--now accomplice--sheds some light on Emperor Genyou's past, giving our heroes the context they need to plot their counterattack! It all comes down to the body-swapping spell and a fateful confrontation from twenty-five years ago. Reirin won't rest until the ultimate sovereign gives Keigetsu and her forbidden magic his blessing!