Septimius Severus was the greatest warrior emperor of Rome because he commanded more legions than any other ruler and expanded the empire to its greatest territorial extent.

“If you were to look at the great warrior emperors of the Roman world, clearly you have Trajan, Septimus Seis, Constantine, early Dlesian etc. But for me, for me it's Septimus Seis. Remember Septimus Seis commanded more legions than any other Roman emperor.”