Every Night, the Slave Princess

"Princess" Renagia is a slave girl acting as the body double of Regnos, a prince masquerading as a princess for his safety in the Italos Kingdom. So when enemy soldiers from the Taringia Empire attack the royal palace, Renagia gets taken hostage immediately and is forced to sleep with Taringia's emperor, Godfrey. Knowing Regnos will come save her one day, Renagia decides to seduce the ruthless Godfrey and use him in order to survive. But that's easier said than done when their past connection resurfaces, blurring the line between revenge and attraction...

(Source: Tappytoon)

Note: Includes six extra chapters.