Kahi is also just scary.
Most groups just select leader by age, there are a few exceptions as shown above. From my observations of Korean and Japanese culture, the 'pecking order' is largely dictated by seniority. Someone who is older or who has just been around longer is more likely to get more privileges. It seems to be more extreme in Korea than in Japan, as I've noticed in shows like Running Man that pretty much the first thing people do after they shake your hand is figure out whether you're older or younger than them. The Korean and Japanese languages are infused with specific words that denote the social status of the person you are addressing, and most of them have to do with age.
I find the 'maknae' position interesting, as it's solely for the youngest member of the group. They almost lose their own name and just get referred to as 'maknae'.