Let's just say, one day, some Chinese dude got pissed about China like way back, and started a war. Now, that war had three separate kingdoms. One of their rulers was a guy called Cao Cao, or 曹操 in Chinese. This war was about the three kings trying to be the first to unite China, and unfortunately, "Cao Cao" didn't really succeed. His son did, and founded some important country, but Cao Cao didn't really care (since he was dead anyway).
His son, then passed the bloodline onto his son, and on, and on, and on, until the bloodline made it to the 20th century and almost none of Cao Cao's blood remain in their veins except for a few of his traits. Some got his bad traits. Some got his good ones. Those descendants also eventually moved to Korea and inherited Korean blood so their own descendants were basically not only Chinese but also Korean. Not surprisingly they also got wizarding blood (obviously there are Korean wizards everywhere now)
Sadly, one of these descendants wasn't very lucky. Namely a woman called June Choi She was happy, with a nice boyfriend who was already engaged to her and shit, when one day her mother decided she didn't like her future son-in-law and told June she already had an arranged marriage and June had to break up with her fiancé. Of course, June didn't do that, and when she met the guy (who called himself Yang Seon) she was supposed to marry to she felt no attraction to him and neither did him. She realized that the guy also had a fiancée himself, and he didn't want anything to do with June and this freaking marriage. Fortunately they got together and found they had loads in common, but to this day, they still have no romantic feelings for each other, and remain friends.
One night right before June got married, she and Yang accidentally got drunk and...well, I'll spare you the details. However, when June found out she was pregnant she freaked out. She didn't know how to tell her fiancé, or how Yang would react, so when she realized her fiancé and Yang had to go somewhere else to work for like a year she was more than delighted since they both wouldn't notice her belly going fatter and fatter.
Just a month before the men came back June bore a baby boy - Justin. She turned the baby over to her sister Jeoine Choi and her husband Lee Park who were both longing for children.
Justin grew up with two major titles above his head: nerd and cute nerd. He wasn't fond of any other titles. He was constantly bullied for some reason and that really didn't help with his self-esteem. He loved reading and inhaled all the books in his aunt's house when he was seven.
Another point: Aunt Jeoine was a witch, but her husband wasn't, so when Justin had his first magic moment when he was eight, Lee had no idea what was happening. Justin was feeling particularly down that day since he was bullied more than usual. He then accidentally, unintentionally, made a lamp explode. Jeoine obviously knew this would happen and that night she explained everything to her husband as simply as possible so his mind would not collapse under the weight of the information given to him in one night.
When Justin was nine his aunt decided it was best for them to move to England since she thought Hogwarts was an ideal place for him to learn and she didn't want to stay in Korea forever. Justin settled in just as his letter to Hogwarts came and Justin left for Hogwarts with hugs, kisses and lots of books.
Justin spent his first few years in the library and - again - inhaling every book he could read. He also finished the said years without much difficulty, and he's hoping to stay that way, despite him getting addicted to video games more and more by the second. Most of all, his biggest question remains unanswered. He's still questioning his own sexuality, and he's hoping someone will answer it, somehow, some day.