The Long Road to Resigning as a Shadow Guard

I transmigrated, but I received none of someone else's memories, and I have no idea where my own memories went. Could anything be more miserable than that? Of course! He was used as a test subject by a perverted mage, tortured by a sadistic instructor, and in the end, actually dumped on a clueless, spoiled brat as a shadow guard. What does it have to do with him whether this kid can hold on to the throne? Absolutely nothing! All right, turns out it does. Position: Shadow Guard; Duties: maid, bodyguard, confidante, poison tester, pillow, thug, encyclopedia, assassin, chef, spy, bedmate... Hours: On call twenty-four hours a day, no days off; Pay: None; Benefits: None; Retirement: None. Supposedly, the previous Shadow Guard worked for 1,123 years and served sixty-seven masters... He wants to quit! He absolutely has to quit! P.S. 1. This is fantasy, um... elves, dragons, magic, divine artifacts... succession to the throne, war, racial issues... All right, I've made this pretty sprawling, so if you're interested, please be patient and keep reading; 2. There are plenty of beauties appearing in the story. I'm a sucker for good looks, but as for the steamy stuff, given the all-powerful river crab's restrictions, you'll have to make do with soup; 3. About the pairing... All right, the wicked mage wins. Core Theme: