Eun was born into a family who valued education very much. Eun enjoyed it, she loved having the knowlegde to the world at her finger tips. When she was younger, she was always curious, wanting to know the answer to everything.  She had access to the best education that could be offered, some of the best tutors, but they didn't prepair her for what happened. When she discovered the light. She had read about it in her books, about magic, people with special powers. She thought they were stories. She tried her best to keep it hidden, but with out knowing how they work, it wasn't long till her parents found out. At first, they worked hard at getting her powers under control, hidden well away from others, growing up with that power, she became more quiet, focused on her studies. She didn't want to hide, but she was told that it would be bad if people found out. Her parents were wanting to protect her. 
She worked hard, mastering her power in a shortish amount of time. 
It was an accident that destoryed her quiet life, and introduced her to the other girls. For just a moment she lost control. A rare moment, that turn out into one of her worst mistakes. She was angry, angry at the injsutice that was happening. There is no reason to hurt those who are less able than them. In that moment, she lost control, and let the world know who was the one with the power of the light. And in that moment, she knew she wanted to get revenge.  

Eun has a quiet air about her. She is often not seen by others, and chooses not to interact much. She is introverted, prefering to be off by herself than with many other people. Eun is the one most people don't pay much attention to. She doesn't mind it at all, she likes working behind the scenes. You will often find her inside, studying, researching, often reading. Or you wont find her. She has an uncanny ability to be found only when she wants to be. Or if she is needed. She has a strong attachment to animals, like most peoples she is fond of cats and dogs, but Eun's true love of animals lies with reptiles and birds of prey. It is a well known fact amoungst people that know her, which only begins to give away the rest of what lies beneith the rest of Eun.
Eun is cunning, she is usually the mastermind behind the plans. She rarely trusts others, always having to have proof. She has to see it to belive it. Somebody who understands risks, and isn't afraid to take them. She operates the game, and can easily identify the other players, sometimes even create other players. She finds it easy to alter parts of the game to fit her liking better, make it easier for her to win. 
Eun is observant, she can easily see things that others may miss, it is a plus side to being the goddess of light. She knows the human nature well, having seen it in play so often.
Eun is kind, and merciful, often holding back the other girls from their wrath. She understands the concept of second chances, and rarely ever lets it get to the point. Most people are aware that they only have one chance with Eun. 
She is calculating, sometimes to the point of being cold, she may be kind, but it only takes one mistake for her to cut you out. It's something she is often critisized for. That is one risk she is not willing to take, the possiblity of being hurt. She has a strong sense of self preservation, but an even stronger sense of loyalty to her family.

Lucifer is the morning star, the angel of light, the most powerful archangel, second only to god himself. That is who Eun is. She is second. Second in everything, and like lucifer, it bothers Eun. Sometimes to the point where she thinks about leaving her sisters. If only she would be recognized for what she has done for them. She does it for the love she bears her sisters, for peace.

PERSONALITY. Junhyung has that cold city chic image, that translates little into his real self. Much like Dai Yu, its a persona. Junhyung is actually pretty easy going and really funny, he may not be the most social of idols, but he is more social than a lot of them. Somebody who is passionate about music, he could spend hours just talking about it. He is definitely a playboy, his friendss joking around that he couldn't count how many ex girlfriends he had with both his hands and feet. He is definitely a clean freak, keeping everything tidy, a tad OCD. When it comes to relationships, he definitely knows what he is doing, a definite flirt. Honesty is the best policy with him, he is pretty blunt, you don't ask unless you want the truth. You can always expect him to be honest with you. He oozes confidence, and even if he doesn't know what he is doing, most of the time, you can even tell. He is actually really tactful, and sometimes even cute, no matter how hard he tries not to be.

MEETING. I have no idea how you plan on doing this, so I'll just put something down and you can change it to something that fits if it doesn't. 
Junhyung is just the kid who loves music, often seen playing an instrument or humming to something. As a student of music, it is understandable. He has always had a strong sense of justice, that eun shares. They met after her powers became known and she met the other girls. It was apart of the mission and he just happend to get caught in the middle. Like litterally in the middle, to which she had to jump in and save him. Even though he will deny it. She had to keep him away from the danger while the other girls got to go and save the day. Which is where they began to get to know each other.