Caspleo:
While watching The Untamed, I have realized that almost all the people have 2 names. Was there any special reason behind having 2 names?
In ancient China, many people had 2 'names', if you want to call them names. When you are born, your parents give you a name consisting of your surname and then a character, so the name is made up of two characters. (such as Wei Ying, Lan Zhan) Wei is the surname (姓), while Ying is the character chosen. In Mandarin, I think this is called 名. When children grow a little older, they are given their second, or official name. This name is used by people you are not as familiar with and have higher seniority with you. This name is called 字.
So basically, your two-character name is used much more in your childhood by people you are close to, and as you grow up, people will start calling you by your official name more often, even your parents and other family members.