Yong-Sun is a humble,down to earth person.He's the type to try to avoid fighting and issues since he grew up with his parents alway fighting which lead them to get a divorce and he lives with his mother so that explain his "umma" charm.He has a calm aura that sometimes make s sleep on him when he talks alot.Unlike s,Yong-Sun always respectful even with children!He can't help it because it's in his nature.He's a good listener and that's why s would always come to him for advices or just want to talk to someone.Beside the fact he's such a sweet person,he does protect s a lot when they are hurt.Other girls tend to become good friends with Yong-Sun that sometime people think there's something between them which makes people think he's a flirt but he's just a nice person.Which leads him to have a lot of scandal.

His fans think he's a sweet angel but sometime he can be a devil when he wants to.When one of wants him to cook them something,he would hand them a bag of ramen and tell them they can do it by themselves.He even has mood swing sometimes when someone too much or make a fool out of him but he'll soon calm down and laugh.When a member is mad at him,he would calmly confront them and nicely talk things out to them and ask for forgiveness.

He  lived with both of his parents at the age nine until his parents had a divorce which later,he lived with his mother and grandparents.Beside having to handle his parents fighting most of his childhood,it was a normal childhood.He would write songs and play guitar for his mother and grandparents a lot.So much that  he grew to love music which encourage him to sing a lot in public parks.which soon made him get spotted to become a SM Town trainee.

During his trainee life,Yong-Sun would always work hard and even developed as a better dancer since his hyung Eunhyuk would teach him the basic of dancing.Soon after a few months of being a trainee,he had to stop since his grandfather had a heart attack which he later died,after that Yong-Sun wasn't the same for awhile but he then moved on since of his future members.Later his year changed,SM Entertainment announced that he will be the leader of the up coming co-ed group Heaven's Door.He was enlightened and hoped he would be a great leader.

Yong-Sun and Bora been dating since she and him were trainees.They are both cute and silly that sometime s call her the "umma" of Heaven's Door.Which makes them blush.He and Bora are always lovey dovey with each other that sometimes it's hard for Bora to hold back her feelings since she just wants to hug him all the time.She even gets jealous when Yong-Sun is being friendly to other girls beside her even s.

Yong-Sun and Bora are very close that they share everything together.He even cooks for her a lot which makes s jealous since he doesn't cook for them as much.They are both the eyesmiling couple and the laughing freak weirdos.

They met during there trainee days which was an automatic click between the two.Orignally they were just friends but then he confessed he loved Bora and then they began to date.They been dating for  four years and still are strong.