Rihyo is someone who loves a challenge. She always pushes herself, both mentally and physically but sometimes she forgets her limits and pushes herself too hard in order to become the best. One thing she hates is making mistakes, if she does then it'll stay with her for a long time, and she finds it difficult to forgive herself which ends up knocking her confidence. This unforgiving trait also applies to other people, because the thing she fears most and hates so much is betrayal. If it is a minor thing then she will forgive you but if it you betray her then she'll forever hold a grudge. This means that due to her guarded personality she doesn't have many friends, but she considers the angels to be the closest friends she has and if she trusts you she will show you her soft side.

She is a great asset to the team as she is extremely loyal and hard working, putting her all into everything. For her age she is considered very mature, but this can be seen as a negative trait to other people because she doesn't appear to have a lot of fun. This maturity is one of the reasons that she likes to be in control. As soon as she's not she panics. She likes to know what's going on around her and is constantly vigilant. From a young age, her parents enrolled her into martial arts, so she is very skilled in both offence and defence and has no qualms about fighting. She loves taking risks, the bigger the better. It's not that she wants to put anyone or the mission in danger, it's because the feeling of success is so much bigger if it pays off. She loves adrenaline filled activities like skydiving, bungee jumping and rock climbing. She has a charming smile that makes her formidable and add that to her charismatic personality and you have someone who draws you in.

People that know Rihyo well will know that she is a soft hearted person with a particular soft spot for vulnerable people or people that need her help. She tends to put other people before herself and this can mean that she neglects herself in the process. People who also help others will leave a good impression on her. She has a knack for talking to people and is quite persuasive when she wants to be. She uses her assets to her advantage, for example she will use aegyo if need be even though she doesn't like it because she knows she has a cute factor about her. She is excellent at handling children and the elderly, and this is one of the only times where her strong front comes off and people can see a sensitive side to her. Generally she is really polite and believes that you should show respect to people who deserve it, hence why she still calls the other angels with formalities; because she respects them.

likes: 
— Being and agent ( It's challenging and keeps her on her toes, as well as being something she loves to do since she gets to help people and fight )
— Food ( She loves food, particularly foreign cuisine )
— Risk taking​ ( She loves the adrenaline rush and the rewards it brings when it pays off )
— Being part of a group ( She likes to play her part and knows that she can rely on the girls to have her back as she has theirs )
— Children ( She likes their innocence and how they are always truthful )
— ​Snow ( Winter is her favourite month, she likes how the snow makes everything look pretty )
— ​Being in control ( Likes to know that she has control of a situation )
— Night time ( It's more peaceful at night and she likes watching the stars )

dislikes:
— Aegyo ( Makes her uncomfortable and she finds it annoying, but she is willing to use it when necessary )
— Making mistakes ( It could end up compromising the mission or putting people in danger )
— ​​Being rude or disrespectful ( People should treat others how they want to be treated )
— Feeling weak or vunerable ( She feels like she needs to be strong for other people and hates feeling useless and weak )
— Being looked down on ( Especially when people assume that she is weaker just because she is a girl )
— Not being in control ( She hates not being in control because she feels powerless )
— Daddy Long legs ( They creep her out )

hobbies: 
— Trains her martial arts skills every day
— Goes for a midnight run every other night
— Reads various books in her spare time

habits: 
— Stares into space when she is thinking
— She clenches her fists when she feels threatened
— Bites her bottom lip when she is nervous
— Cracks her joints when she is tired
— Taps her foot when she gets bored or impatient

trivia: 
— Has several fears ( Isolation, failure, death ) 
— She took part in a mixed martial arts competition and dislocated her arm, but continued to fight and won, and ended up breaking her arm in the process, resulting in a scar on her left arm 
— She has a small charm bracelet that her parents got for her 16th birthday
— Always wears a silver necklace that Kyungsoo buys her
— Carries a small photo of her parents with her and keeps it with her when she goes on missions but conceals it
— Ambidextrous (though primarily right handed) 
— Likes to go out at night to clear her head
— Wanted to be a doctor when she was younger
— Favourite colour is blue
 

Rihyo was brought up as the only daughter of two wealthy parents. Her parents worked almost all the time, her dad as a 'banker' and her mum as a Korean-Chinese translator. Her family originally lived in Incheon, but her parents moved her to Seoul when her dads job needed him to move. Her father taught her english since she was born, and she only learnt chinese when she moved, her mother thinking it was a good idea since there were some Chinese kids in the neighbourhood and Rihyo had trouble communicating with them. Because her parents were away so much, they didnt want her to get bored so they sent her off to learn martial arts. However, that was only the reason she was told, but not actually the real reason her parents sent her. In fact, her parents wanted her to learn how to defend herself because they knew that people were out to get them. In reality, they moved to Seoul because her father was actually an undercover agent himself-one of the most prestigious, but he and his team had failed his last mission and this resulted in the people he was supposed to be going after, coming after him instead. So they wanted Rihyo to become a strong person who could end up defending herself if need be. Rihyo was too young to know this, but continued going to her classes where she quickly became one of the best students. By the time she was 16, she had mastered most martial arts and was quite formidable. At one of Rihyos competitions, she ended up breaking her arm after refusing to give up after initially dislocating her arm. Her parents took her to the hospital to get her fixed up and she was in there for a couple of days before they decided to let her go with a cast on her arm. After 6 months, the cast was finally removed and she could use her arm like normal, though there was a scar left behind.

A day after she turned 17, a group of people kidnapped her and although she put up a good fight, there were too many of them for her to fight by herself. The kidnappers held her hostage and said they just wanted her father. When she asked who they were they replied with "The Dark Devil". Her father came to rescue her where she learnt the truth behind her fathers real job, and also where he traded his life for hers. Rihyo barely managed to escape whilst the Dark Devil took care of her father, and ran home only to find her mother also dead on the floor. The police turned up and took care of her until she could find a place to stay, namely renting out an apartment through one of her dads friends. She was very grateful to the police for helping her, and they inspired her to join the Police Academy. When she turned 20 a couple of years later, she had already graduated from the Police Academy with top marks and went straight into action. Barely a week had passed since she graduated, and she knew that someone had been following her during that time. So instead of facing them out in the open she decided to lure them into a secluded alleyway where she fought the person until she had him facing up against the wall with both his arms pinned behind his back. She expected him to be from the Dark Devil, and so was surprised when he said he was from a secret agency called the SAA, and his name was Chan Shik. He had been watching her for some time-since they moved to seoul-and wanted her to join the team. He explained what the SAA was and that it would pose more of a challenege for her than if she stayed as part of the Police. She was wary of this SAA but agreed to join on the condition that she done things her own way, secretly intrigued to learn that it would be more challenging for her. When he agreed he lead her to the SAA headquaters and introduced her to the rest of the team (the other girls). He also revealed to her how her father had been one of the best agents belonging to their sister association, and had failed his last mission which was the reason for his death. From that moment on Rihyo decided to follow in the footsteps of her father and hoped that one day she could get revenge on the Dark Devil.