Reborn as a Substitute Bride, the Princess Is the Tyrannical Eunuch's Obsession

[Both pure + devoted affection + palace and household intrigue + violent eunuch lord + sweet, gentle princess] Ling Qi, the third princess born to a disgraced consort and raised in the Cold Palace, and Jing You, the spoiled and overbearing second princess, are both reborn. In their previous lives, the beloved second princess, their second imperial sister Jing You, was betrothed to Li Chongzhen, heir to a marquis household who held immense power at court. But on their wedding night, Li Chongzhen handed her over to the cruel and vicious Ninth Eunuch. Unable to endure years of torment and abuse, the princess took her own life... The third princess Ling Qi devoted herself to studying medicine in the imperial palace. She later became a princess sent to marry a vassal lord, who cherished her and remained utterly loyal to her. His power grew by the day until he finally conquered the imperial clan and changed the dynasty. Ling Qi went from being a princess sent to marry a vassal lord to the founding empress. In this life, the two suddenly faint during their coming-of-age ceremony. When her elder sister wakes, she swears to switch marriage partners with Ling Qi: she will make Ling Qi suffer the torment and abuse of being played with by a eunuch, while she becomes the vassal lord’s favorite and ultimately the new dynasty’s founding empress, basking in honor and glory. In the end, after her elder sister is sent away to marry, she never becomes the new empress. Instead, the third princess becomes the beloved favorite of the Eastern Depot’s Chief Eunuch, possessing every honor and privilege.