Ga-Yun lived in Korea until she moved to London to pursue an education at Hogwarts. She is a pureblood. Ga-Yun lived in Incheon, Korea and was born there.
Even though she lives in London, she only lives in the dorms in Hogwarts. For the holidays, she goes back to Korea to visit her family.
Ga-Yun is indeed smart, but always considered the ugly duckling. She didn't particularly care for comments like that, but they still hurt her.
In her first year, she befriended Henry Park, Silver Lee, and more. It was clear she had a crush on Henry, but she was aware that Henry and Silver liked each other, so she decided to stay quiet. When they got together, Ga-Yun was sad, but she managed to get over her crush on him. Sometimes, however, she relapses and has a tiny crush on him again. Ga-Yun often offers relationship advice for Henry and Silver.
Ga-Yun ended the year with average marks for a Ravenclaw.
In her second year, Ga-Yun was still the 'ugly duckling', but Henry and Silver were pursued by countless people. She gets jealous of that sometimes, but still loves them as friends.
This year, she gets an owl and names him Sui. Sui is brown with a white underbelly, and his wings are about three feet long.
Also, this year, Ga-Yun shows a fondness for music.
She ends the year with average marks again.
In her third year, Ga-Yun was thinking of trying to find a boyfriend. So far, there's no one she wants to date. Henry and Silver, however, are willing to help anytime, but Ga-Yun's too stubborn to let them.
Since Henry's having some trouble trying to protect Silver, Ga-Yun decided to help along, while also looking for a guy.
Ga-Yun is stubborn and is short-tempered. However, she is patient with her close friends, and is a bit childish. Ga-Yun hates being left behind and she hates being called an ugly duckling. She doesn't usually trust people she's aquaintances with, or show them a personality that her friends know. Ga-Yun hates people that talk behind other people's backs, people who always interfer, and people that treat other people badly.
To strangers, she's quiet and acts mature. She hardly speaks to them and never acknowledges them. To her close friends, she shows them things that she would never dare show anyone else.
Ga-Yun relies on others a lot and is a bit clumsy. However, once she gets into something, she really gets into it.
Also, Ga-Yun wants a relationship to be a cliche type, where the girl supports the boy with all her might, and the boy protects her forever. She wants to be able to be a girlfriend that can cheer him on, but easily comfort him too. In a guy, she wants him to be honest, trustworthy and brave, but smart. She isn't fond of players, or cocky guys.
Ga-Yun is incredibly biased, but doesn't really show it to people other than Henry and Silver. She prefers Asian friends over any other types of friends, and she doesn't want to date other guys that aren't Asian. Henry and Silver don't really mind about her biased thoughts, and they easily brush it off.
Henry Park and Ga-Yun are close friends. Ga-Yun used to have a crush on Henry, before he and Silver Lee started dating. However, now that they are a couple. Ga-Yun supports them 100%, even though she sometimes has crushes on Henry again. Ga-Yun loves the fact that her two best friends are dating, and she doesn't want them to fall apart.
She hates people who try to break their relationship, but she knows that it isn't easy to do so.
Ga-Yun occasionally helps Henry protect Silver from guys, while trying to find a boyfriend for herself. Henry offers help to get one for her, but she refuses, saying that she has to find him herself.
Silver Lee and Ga-Yun are also close friends. She and Ga-Yun are room mates. Ga-Yun supports Silver's and Henry's relationship and don't want them to break apart from each other. Ga-Yun and Silver are super close and share things with each other. They often go to the library together, along with Henry.
Silver offers to get her a guy, but Ga-Yun refuses, saying she has to find him herself.
Silver has no respect for anyone that calls Ga-Yun ugly, which she is not. She also supports Ga-Yun all the time, for anything.