Community maganers Community managers are the heart of okayu.me. They handle reports, and cheaters, accept(or reject) ban appeals, plan events, select BATs. They are also here to help with your daily questions.
Owner Developers add new features to the server, squash bugs, keep the server up and running and take care of its maintenance. You can distinguish them because they have a blue name in game chat.
Overwatchers These guys responsible for banning cheaters and bad people.
BATs BATs play beatmaps in the ranking queue and decide whether they are good enough to be ranked or not.
Donators or Respected People's They're persons, who help server with pull requests or support server with donation.