Grand or Raid Bosses (RB) are mobs which are supposed to be defeated by a party of several players. RB can dwell either in instanced zones or in other game zones. To get information about the dwelling place of a boss, you need to open the map (M hotkey), press the “World Info” button, and choose the “Recommended tip” tab (press the 'Raid' button).
Be aware, that raid bosses spawns are based on server timezone, so it might be different from your local time.
Normal Raid Bosses: 24 Hours + 0-12 Hours Random.
Special Zone Raid Bosses: 21:00 (every day).
Instance Bosses are limited to Instances reset timer.
