Rias

Rias (real name Saeyoon Choi), is one of the main antagonists of the Mystic Messenger. She is the identical triplet sister of Saeyoung and Saeran Choi and a disciple of the organization Mint Eye. During visual novel sequences, prior to the revelation of her identity, her name would be displayed as three question marks (???). In Another Story, Saeyoon continues to use the screen name Rias, but now goes by the alias Ryuk. As of January 31, 2018 she is able to romance Unknown as Ray in Another Story.

Casual & Deep Story
Saeyoon is very hostile and defensive towards everyone, particularly her triplet brother, Saeyoung (707). This is due to having been "brainwashed," drugged, and tricked into believing she and Saeran were abandoned by Saeyoung when they were younger. She has become very paranoid and refuses to trust anyone except for Saeran for fear of being betrayed again.

Another Story
In Another Story, Saeyoon has two different personalities, Ryuk and Rias, which is likely a side effect from ingesting Mint Eye's elixir of salvation for several years. The two personalities are aware of each other and are able to communicate with one another. As a hacker, Ryuk and Rias have extremely different skill sets with Ryuk's skills being on par or even being better than Saeyoung and Lilith combined. At the moment which one is Saeyoon's original personality is unknown.

For the majority of the route, Ryuk is the dominant personality. She is gentle, sweet, and terrified of being abandoned. She is against violence, and cannot bring herself to hurt another living being. Ryuk was also terrified of having Rias' personality awakening and taking over.

On the other hand, Rias is the complete opposite of Ryuk and is extremely dark in nature. She desires the destruction of the RFA and those that oppose Mint Eye, Saeran and her. Rias is a cold type of person, and often acts cruel for the sake of being cruel to the point of being the cruelest. She tends to act rude and ridicules people she does not approve of and her temper tends to get the better of her when things do not go her way. Rias is also a sadist who lacks empathy for people of whom she deems weak, since she lives by her father's philosophy ("The strong survive and the weak die"). She enjoys putting her enemies through great pain, both physically and emotionally. She has no qualms about killing innocent people to get what she wants, and rationalizes her behavior with her father's old creed.

Rias was mostly suppressed by the effects of the elixir of salvation, but Ryuk's last dosage had her taking over Saeyoon's body. Saying Saeyoon's name also has the effect of awakening Rias. Rias seemed to hate Ryuk, calling the other personality a marshmallow girl, and disliked Ryuk's crying and whining.

Appearance
She has white hair and mint-colored eyes. At several points of the story events, she wears a black mask that covers the lower half of her face.

In Another Story, as Ryuk, her hair is better groomed. She wears a magenta dress, with a blue rose pinned to the lapel. However, after her personality has changed to Rias, she wears a black dress with silver chain collar tips.

In the past, she had scruffy vermilion hair and golden eyes like Seven.

Background
Saeyoon, along with Saeyoung and Saeran, is the illegitimatedaughter of a high-ranking politician. Shortly after birth, their alcoholic mother exploited their identities by forcing their father to pay hush money. During her childhood years, she, Saeran and Saeyoung were abused by their mother, but she and Saeran received the brunt of it due to becoming ill more often than their triplet and, being "weaker", they could not attend church when Saeyoung did. Her fondest memories were eating ice cream and sneaking out of her room to see the sky for the first time with Saeyoung and Saeran.

Saeyoung dedicated himself to freeing his siblings as well as himself by learning how to hack from a textbook. Unfortunately, as Saeyoung's ability to hack grew to a professional level, Saeran and Saeyoon were left behind, as their triplet was offered a promising job by V that would free him and his siblings, but with the price of not telling Saeran and Saeyoon where he was going. After Saeyoung's disappearance, Saeran and Saeyoon were more vulnerable than before, their mental state extremely fragile, and their mother's abuse became more vicious than ever.

Under V's promise to Saeyoung to protect Saeran and Saeyoon, he and Rika then paid a visit to their house, making a compromise with his mother to let them attend church school, or else they would expose her abusive behavior. One day, after Rika took a picture of Saeran and Saeyoon to send to Saeyoung, she gave them a textbook on hacking, asking them to keep it a secret and believing in their potential.

Shortly after Saeyoung had left and five (or eight) years prior to the start of the game, Rika kidnapped and recruited both Saeran and Saeyoon into Mint Eye, where they were forced to take numerous substances and brainwashed to believe that Saeyoung had purposefully abandoned them because they were both burdens.

C
Saeyoon is presumed to have been initially close to C, as C, V and Rika took in Saeran and Saeyoon and treated them as family while Seven was forced to leave them to work as a secret agent towards a better future for the three of them. However, after being brainwashed by Rika which C initially wasn't aware of, she shows great animosity towards C, and even accidentally kills her in first-of-two parts of the secret ending. In V's route as Ryuk, she tends to be more gentle and softened towards her.

Vale
During Zen's route, she will be almost kidnapped by her and Unknown (Saeran) until Zen saves her from both of them, which leaves her initially scared and traumatized for a long time. However, within the other routes, Vale will be disturbed and cautious of the mysterious hacker, not knowing who the person is.

707/Saeyoung
Seven is Saeyoon's older triplet brother.

When they were young, their father ran in the presidential election and their mother constantly blackmailed him to send them money, lest she reveals the existence of their three children. Her mother was said to abuse Saeran and Saeyoon as they were weaker and fell sick more often than Seven.

Seven trained himself to hack and took it upon himself to help his siblings and himself to have a good future. However, Seven met C, V and Rika at church, who convinced him to join them - on the condition that he leave Saeran and Sayoon behind.

While at the Mint Eye, Saeyoon was given drugs, which were used as a method of brainwashing. Saeyoon was told that Seven had abandoned her and Saeran, which caused them to beginning feeling resentment towards their brother, even causing them to shoot and kill Seven in the 3rd bad relationship ending. However, at the end of Seven's Good Ending, Saeyoon and Saeran apologize for their acts, and their ties with Seven are restored.

Unknown/Saeran
He behaves much kinder to Saeyoon, in comparison to other people. He treats Saeyoon like a princess and soon grows to obsess over her, wanting only for her to be happy and stay with him at Mint Eye.

Mother Choi
Kept solely as leverage to blackmail Saejoong Choi for money, she abused both Saeran and Saeyoon for being the weaker and more sickly of the triplets. Their punishments included being tied up, beaten, starved and/or dehydrated for a prolonged period (often few days at a time). This was worsen by her alcoholism.

In Yoosung's route, it is implied that she was murdered (presumably by Saeran and Saeyoon). However, it was confirmed by Saeyoon's diary in the Mint Eye Believer's package that she and Saeran escaped shortly before she died. Though it appears to potentially be a murder, investigators cannot find out who did it and chalk it up to a suicide. Saeyoon and Saeran were seen mourning her death despite the abuse they endured from her.

This implies that Saeran and Saeyoon did in fact love their mother however it is unlikely this was reciprocated.

Ray's Route

 * "Oh, I almost yawned in front of the believers."
 * "I'll die young one day."
 * "Huh? My face is cute? Why, thank you big brother."
 * "All This time, I seriously thought that it's better to die than to live your life alone."

Trivia

 * Being the triplet sister of Seven, Saeyoon's hair and eyes color were originally the same as his.
 * She dyed it white at some point. At the end of Secret 02, it appears to have reverted to the same shade of red as Seven's.
 * There is also a possibility that Saeyoon's white hair is due to a syndrome called Marie Antoinette Syndrome which one's hair rapidly turns white due to extreme amount of stress, shocking news, fits of rage and extreme fear and anxiety.
 * Her first appearance has her having mint colored eyes. At the end of Secrets 02, her eyes remain the same. It is implied that she probably wears contacts or it was a side-effect of the elixir used by Mint Eye.
 * It is implied in a story mode on day 10 Yoosung's route, that Saeran and Saeyoon killed their mother.
 * However in Ray's Route Good End, it was Rika who killed the mother.
 * In 707's After Ending, Rias - under her real name, Saeyoon - stated that she has no interest in men; however, this is only stated in Seven's dream. There is neither proof nor confirmation of what her sexuality is.
 * In the second Secret Ending, it's told that Saeyoon has a stress-related gastritis and a mild mental disorder, although it's not specified what kind. Her immunity system is also low, presumably from the different drugs she was given.
 * It's also heavily implied that she suffers from depression, clearly stating that she wants to die and even tries to kill herself before being stopped by Saeran.
 * It is also stated that she was sickly as a child, which may relate to the low immunity she is noted to have when she's hospitalized in Secret 02.
 * While not official, Saeyoon's voice actor interprets Saeyoon as having Borderline Personality Disorder (which she herself has), and mentions it in her Free Talk for Secret 02.
 * According to the RFA Top Secret Book:
 * Her email is rias@cheritz.com
 * She holds a special talent for hacking.
 * She likes ice cream and candy, and dislikes bread.
 * Her most used app is the GPS.
 * Her favorite quote is, "Life is always full of unfairness."
 * Ryuk is currently studying the language of flowers.
 * Ryuk considers flowers to be her only friends.
 * Of all the female main characters, Saeyoon is the only one with two different greeting icons on the game's homepage. One for Ryuk, and a masked one for Rias.
 * C also has two different greeting icons, albeit less obvious. One without sunglasses, and one with sunglasses.