Carter Hwang was born into the pure-blood Hwang family two years after his sister Min-Young was born and then adopted by an unknown family, and a year after his brother Hyun-Ki was born. At the time of his birth, Carter was named Hwang Chae-Yeol by his parents Dong-Hae and Bo-Mi. Growing up, Chae-Yeol was never informed that he had a sister somewhere out there in the world, he was led to believe that Hyun-Ki was his only sibling, and Hyun-Ki was told the same thing. Dong-Hae and Bo-Mi, despite believing they could raise their children, never did an overly good job at doing so. Being young themselves, they often went off on their own little adventures and hired nannies to raise Chae-Yeol and Hyun-Ki.
It wasn't long until Chae-Yeol was taught how to use his magical skills at the age of four, as his nanny Seol-Hyun was also a pure-blood wizard who had attended a wizarding school. Seol-Hyun taught Chae-Yeol most of the things she knew about magic, but left some of it for his parents to explain when it was time for Chae-Yeol and Hyun-Ki to attend a wizarding school themselves. But until that time came, Seol-Hyun continued to teach the brothers about magic.
All was well for Chae-Yeol, after all Dong-Hae and Bo-Mi were planning on moving the family to England after Bo-Mi had gotten a job offer in Gloucester. But when the two went to go look for a house to buy, they had went missing and were never found. A month after, Seol-Hyun had then legally adopted Chae-Yeol and Hyun-Ki. After following their parents wishes she moved to Gloucester with Chae-Yeol and Hyun-Ki at the age of six and seven respectively.
Upon their arrival in Gloucester, Chae-Yeol and Hyun-Ki had their names legally changed to Carter Hwang and Liam Hwang respectively. Seol-Hyun continued to teach Carter about the magical world up until the age of eight, and since his parents were no longer around to inform him of Hogwarts, she took it upon herself to give him the needed information about the school, and informed Liam that he'd be going when he turned eleven years of age. After Liam was sent to Hogwarts, Carter often felt lost without his brother there to look up to.
Carter's attitude stayed like this for a year, until it was time for him to attend Hogwarts as well. When it was time for him to leave, he thanked Seol-Hyun for everything she had done for him and Liam. Before he left though, Seol-Hyun gave Carter a letter that was writing by his mother Bo-Mi, and instructed him not to read it until he was with Liam. After leaving for Hogwarts, Carter was welcomed by Liam and when the two were alone they read the letter from their mother. In the letter it explained to them about their sister who might be attending Hogwarts.
Carter is now midway through his schooling at Hogwarts, and he has still yet to find the identity of his sister.