Antonius is an Non-Player-Character included in the list of Neighbors automatically(it is actually in a separate list.
His Island was originally intended to be an example of how to build your city, but often the developers break game rules players have to follow when they lay out his island, making it of questionable use. For instance, Players are limited to one Mill in their Empire, but Antonius has been sometimes seen with 4 Mills on one island.
Antonius is always shown as level 25, but unlike Antonius players will not clear all the Wilderness from their own islands until they reach level 31, which also causes confusion.
"Antonius Cheats!" is a common running joke on the My Empire Forums.