They always post around a certain time. We can deduce the hacker lives and operates in the Seoul area as they are aware of events that happen within the city, so we can lower the scope of the search just to Seoul. It's safe to assume the hacker is not from the elite class, given the quips about the lower classes. A native Korean, based on the language. They frequent Jisoo's cafes and Dr. Kang's Veterinary offices. You can try blocking the IP range so they're forced to only use local IP addresses and whittle it down from there.