Administrator (アドミニストレータ Adominisutorēta) is the group of seven people who developed the supercomputer "Schuster".
Z/X Encyclopedia Entry
The seven genius engineers who developed the supercomputer "Schuster" that rules the Blue World, they are known as "Administrator".
Their bodies has been lost for a long time, but all their memories have been recorded to computers. When they appear before humans, it is only a remote controlled humanoid android called avatar. They are what one would call a data human.
Usually, the bodies of the Administrator are hidden together with the mirror copies of Schuster throughout the world, their whereabouts are unknown to one another. Also, each of them is guarded by a member of the Original XIII. The Original XIII that protect them can only be dispatched to the other place if a huge crisis is happening.