She was born in South Korea, to a goddess and supporting father. Her mother was Cybele, her father a young man of 20. However, little had Cybele known the "mortal man" she had slept with was a son of Aphrodite but he knew that Cybele was a goddess. Her father remarried when Ki-Jae was three. She grew up happily, her father a successful businessman and her stepmother a model. At a young age, it became obvious Ki-Jae was going to be a stunner when she grew older. Her mother got requests to have Ki-Jae model for children's brands but she declined, stating her daughter was too young.
From a young age, Ki-Jae was trained by her father because he was a demigod himself and he knew the risks. She was trained in knives and swords from five and it all came in handy when her first monster attack occurred at eleven. Her father and her had been walking down a back alley, late for school when the hellhound came out of nowhere. Whilst her father handled the situation, Ki-Jae remained calm and defended herself.
When Ki-Jae reached high-school however, she began modelling with permission from her parent's. She continued this as a career once she graduated. Whilst she wasn't internationally famous, she did have quite a bit of fame in South Korea. Despite many monster attacks, Ki-Jae was able to avoid danger by fighting alone and with her father whilst also keeping up her modelling. This is how she met Jin-sun. He was working on the same shoot as hers and gods, they hated each other at first sight. He was stuck-up and rich while she remained down to earth despite her fame. He was loud and got angry easy while she was quite timid but not afraid to stick up for herself.
This was when Eros got involved. Finding two people forced to work together who hated each other was so amusing to Eros that Eros decided meddled in their mortal lives, forcing them to fall in love. It was a destructive relationship from the moment it began. Nearly as destructive as the monster attacks that plagued her nightmares, as the hour long shoots without food that made her stomach cave and her skin pale.
Despite their constant arguments and destructive behaviour towards each other, they truly believed they loved each other. When a crazed armed robber broke into the bank they were putting money in, Ki-Jae's life fell apart. Ji-Sun tried to act like some hero, confronting the armed man. The bullet was released from the gun but Ki-Jae would not let her first and only love die. She leaped in front of the bullet and was taken to hospital, bleeding out. The gunman, feeling so guilty having not meant to actually shoot someone, allowed someone to take him in as he cried hysterically saying it was an accident.
Eros, having watched over these two destructive lovers for a while, felt regret. Ki-Jae had a bright future in modelling ahead of her and she was much too young to pass at only eighteen. She had loved Ji-Sun so much she had died for him. Along with that, Cybele would be quite angry if her demigod daughter died because of his reckless amusement and Eros would rather avoid a confrontation. Eros visited the hospital and gave her an offer. He would request for Apollo to heal her in return for her going to Camp Half Blood and being the Priestess of his cabin. Ki-Jae, knowing she had much to live for and so much life ahead of her, accepted.