Mike Nysul who gave his name to the spell Nystul's Magic Aura. Eventually Nystul also became a character in the Greyhawk setting. Later Greyhawk products describe Nystul as a citizen of Greyhawk's Duchy of Tehn where he, during the Greyhawk Wars, was active in evacuating refugees from the realm, as it was being invaded by outside forces.
Time to put on my Blackmoor glasses. Blackmoor's Duchy of Ten and Greyhawk's Duchy of Tehn both come from a realm in the C&C Society Setting. Blackmoor's Duchy of Ten also suffered from invading forces, which we know as the Afridhi under the leadership of Toska Rusa, Bride of Zugzul. Could not Blackmoor also have a Nystul the Wizard? The Tenians sure could use all the help they can get.
This got even more fun when I learned that Nystul also is a wizard in the Ultima games, which is where the image above is borrowed from.
More discussion of Nystul and Blackmoor's Duchy of Ten here!