SPOILERS AHEAD, READ AT YOUR OWN DISCRETION!
If you haven't played Mystic Messenger completely, you might read something that will reveal to you the complete story of the game. So please pay attention!
Saejoong Choi is the current prime minister and one of the two main antagonists in Ray's route. He is also the illegitimate father of Saeyoung Choi (707) and Saeran Choi (Unknown/ Ray).
Personality
Saejoong Choi is a political figure who is well-liked for his honesty and kindness, and it is said in Another Story that he is likely to be a successful politician with a chance of being elected as the next president. It is later revealed that this Saejoong, who is loved by the public, is the polar opposite of his real self. He is extremely violent towards his sons, apparently having tried relentlessly to find and kill them when they were young. He later goes so far as to kidnap 707 in an attempt to obtain information about his brother.
Saejoong has committed a series of illegal acts, such as bribing police, to maintain his perfect image.
Appearance
Saejoong Choi is said to be fairly good-looking for a politician (affirmed by Zen). He has brown hair and golden eyes. It is shown that he looks similar to 707, which starts the questions at first place.
He has a good build, and in his only sprite he is seen to be wearing a brown suit, white shirt, and dark brown tie, and has a beige coat draped on his arm at all times.
Role
Background
Around 20 years ago before the events of the game, Saejoong Choi had an affair with Mother Choi - despite being a husband and father - who later gave birth illegitimately to Saeyoung Choi and Saeran Choi. Mother Choi blackmailed him into giving her money in exchange for hiding the twins, fearing their existence would ruin his political career. Overtime, however, he grew paranoid and obsessively attempted to get his sons killed.