I have the same setup as you do @akaii, Keymaster is a custom changed name for Super Administrator. If you are on a multi-site network it controls all the WordPress installations and over the adminstrators.
Administrators however can only control one WordPress installation. Such as me on two of my web network setups, I am both a Keymaster and administrator.
Hope that helps. By the way a keymaster is a reference to a Ghostbusters scene I believe. Someone with Ghost Busters terminology that assigned this on WordPress needs to find a new hobby. 😀
Awesome job Stefan, Thank You for the help!
