Destination: Imperator Italicus.

There is a unit, in that charming Recruitment Viewer, available for many faction with the title; Imperator Italicus.

Now, this isn't going to be as straightforward as it sounds - and I certainly have some deed to accomplish before I can obtain it - because as the Arverni I control more than two thirds of Italy, and I see no such unit.

So tell me, is it a fire-breathing Dragon?

They're Italian mercenary generals and they use the same model/stats as Campanian cavalry. Try building a level 5 regional MIC in Italy.

Or just a level 4 governement, and he'll appear as local governator.