The story to my OC #1. I called The Vampire knight

A princess takes in a vampire to be her personal gaurd when war isn't happening, but when it is (and it happens often) he's on the front lines and wipes out every opposing soldier on the battlefield. Later in the tale he single handedly took out an army of 10,000 men. The vampire has a crush on the princess and he owes her everything, the king only allows him to ve around her because he's the strongest of the strong but not for very long. In fact he hates vampires. Later the princess is found dead in her garden the knight finds her but is blamed for it then is sealed away. The sickness that took the princess was a deadly plague that eventually took the entire kingdom shortly after. A few survivors lived on through the passing merchants that found the kingdom had fallen. The tales lived on and fell into ruin, then into legend, to a fairytale, then to myth. One book remained, and fell into the hands of a little girl who grew up reading it, the book tells of a glorious kingdom and a strong knight of legendary strength. It was never said that he was a vampire because the populace didn't know, but later in brick cover layed a secret note. It explains where the castle was located and that the knight could be revived and that loads of gold lay where he rested. By that time she was old enough to go on excavations with her father and now they are going to the kingdom of ruin high in the mountains in a plateau in the middle of the peek, hidden away. The father was after the gold, and the daughter the knight. Little do they know that they are the king and princess reincarnated.
Id like to start from the very beginning of the vampires tale and take it from there