
This can be seen in his own route (where he becomes irritable after the hacker's identity is revealed to be Saeran), Jumin's and Yoosung's routes, and V's After Ending where the characters remark he spent two years not making any jokes and being serious, due to Saeran being missing. Once its revealed that Saeran is unhappy, he can no longer keep up this façade. A common pattern with Seven, is that if he believes Saeran to be happy and safe, he acts like the energetic and jokster 707 in the chatrooms.
This all changed when Seven received a floppy disk with Saeran's smiling photographs on his 20th Birthday from Rika, showing how happy Saeran was after Seven left.
Vanderwood mentions that Seven used to be a serious workaholic with a robotic personality who studied during the day, worked at night, and barely slept. In spite of that, in an outgoing call in the first day of his route, Seven states that because he is one of the smallest agents at his agency, he takes up jobs that require to dress him as a woman. Seven underwent physical training as part of his training as a secret agent. After two days, the police investigations revealed that he was never enrolled since the beginning according to the college's admission records. Further information about his college life is provided in Rika's book in Cheritz's Mint Eye package he studied in a university in the USA under the fake identity of Chilyoung Choi (19 years old), and suddenly went missing one day, leaving no traces behind, not even hair or fingerprints in his own room. In Yoosung's route, Seven hints that he studied at an Ivy league school. It's possible that he lied about his age in the profile since he's under a fake identity or that this was a later retcon done since Ray's route to make the twins' ages better fit the game's events and timeline. However, the game's timeline and Zen's speech in Ray's Good Ending make it clear he's actually older 22 years old in Another Story and 23 years old in Deep/Casual Story (internationally). In the game's promotional material, Seven is stated to be 22 years old in Korean age, and 21 years old internationally. Seven states as long as there's a connection, he doesn't limit his preference to women, revealing that he could be part of the LGBT community. His favorite quote is: "It's not that people have humor. In the character design notes, Seven was made wears glasses due to fan interest in having characters that wear them, since previous Cheritz games never had a "pursuable" character wearing glasses with a route before. His route was the last one being written during the game's development before it's official release in 2016. Seven's phone number is +82)10-7070-&O&X and his email is Seven claims to be fluent in seventeen languages. 707 MYSTIC MESSENGER WIG PASSWORD
In April Fool's DLC, his login id and password of the messenger are '707' and 'ga!axyStar$xo' respectively.It's also worthy of note that "lol" in the original Korean is ㅋㅋㅋ. However, in an outgoing call on the 8th Day of Ray's route, Seven claims there might not be any meaning attached to his handle, and that it being able to be read upside down is just lucky coincidence.707 flipped upside-down is 'LOL', with his online name possibly referencing his tendency to say 'lol'.then it'll be a history changing miracle." He did this to remind him not to become like his parents and to keep his promise of protecting Saeran. Seven's baptismal name, Luciel was chosen by him as a reference to Lucifer's Angel name to remind him to not fall into darkness.As a secret agent, he works under the codename "707 EXTREME".He's infamous for being the character that breaks the 4th wall the most, often as a comedic device.
Seven won the 2018 Cheritz's popularity poll as the most popular character in the game.