Brand Ek, he is the pure-blood prince of the vampire clan, but he does not want to stay in the original world anymore, so he comes to the world of HP with his blood servant An.
Merlin: [Smiling and stroking his beard] If you don't want to be chased by "that person", how about you agree to my three 'little requests'?
Brand: [raises eyebrows]
Merlin: From now on, your name will be Brand Ek Slytherin, and I would like to ask you to raise a little bun.
Brand: [Impatiently] Name.
Merlin: [laughing] Tom Marvolo Riddle, and when the Duke finds him, please change his name: 'Voldemort'. Then he could do as he pleased with the Duke. As for the location, the Duke will naturally know it by then.
Thus, Brand Ek Slytherin officially entered the world of HP.
Target: None. No, it's to raise Baozi and deal with two Mary Sues by the way?