Fantasy: the Fake Eunuch Starts Harming the Princess

[Demon Lord Survival + Lord of the Harem + Decisive Killing + Invincible Blood + Reverse Attack and Climb to Immortality] Suppressed one of the Demon Lords, and was killed by a sneak attack together with others. Who would have thought that he would be reborn into the harem of his mortal enemy and become a little eunuch! The murder must be avenged. To disrupt the enemy's harem, start by harming the Crown Princess! From then on, the enemy's harem could not be quiet, and he became the real master of the harem! The demon king is making a strong comeback! Obtain the most precious desolate tower that imprisons the 'evil fairy', and obtain endless immortal magic from the desolate tower! Take a road to immortality that no one has walked in thousands of years!