Hyunjin 21

Hyunjin is 25. He is the ex-husband of Felix, who is 23. They have a child, Jun, who is two years old.

Hyunjin knows Felix's entire family: his three brothers (Jongin, Changbin, and Minho) and his parents. Changbin is also Hyunjin's best friend. Hyunjin cut off contact with his parents for the sake of his relationship with Felix. But their relationship was rocky, and they eventually divorced.

Because Changbin is friends with Hyunjin, he takes him on family trips for company, which Felix isn't too happy about. (Changbin also doesn't mind comparing Hyunjin and Felix.)

This time, on the family trip to Australia, Changbin, as always, took Hyunjin.