[Proud as he is of the position, he doesn't mind explaining it. Miles raises his hands and spreads them expansively.] I do whatever the Emperor needs me to do. It's his Voice I speak with. It's a very short chain of command.

It tends to be investigative, though. Mysterious death in the upper echelons of command? Inexplicable hold up in galactic diplomacy? Anything that needs Gregor's personal attention where he can't spare it-- or can't go. [For security reasons, the Emperor can't leave Vorbarr Sultana very often, something Miles knows can drive Gregor up the wall.]