TikTok Agencies?

I'm currently watching a streamer from South Korea. I learned that he's a part of an agency, and I can't find any information about what that means. I've looked through some Reddit threads, and can only find what it means for American TikTok, and even then there's not a lot. What does the agency do? Is it true they get bonuses based on how high their live ranking is, and is it true they get a cut of TikTok's half of the gift money and not the hosts? What does the live ranking do for streamers, and why do the agencies care so much about the ranking? Is there somewhere I could find out more about this?