9. Hannibal
One of the greatest generals of antiquity, Hannibal lead the forces of Carthage against Rome in the Second Punic War. Hannibal's father lead Carthaginian force during the first Punic War and imparted a sense of hatred in Hannibal towards Rome. Hannibal's most famous feat was leading his army on a daring overland attack on Italy that crossed both the Alps and the Pyrenees while fighting off native tribes of Gaul's. If it wasn't hard enough taking a normal army over both mountain ranges, Hannibal also took war elephants along with him. Another one of Hannibal's most famous achievements was the Battle of Cannae which is often regarded as one of the greatest tactical triumphs in military history as Hannibal virtually annihilated a numerically superior roman army. Hannibal ended up rampaging across Italy for years before a Roman counterattack on Carthage forced him to return home where he was ultimately defeated. A film adaption of Hannibal would almost be like a modern Spartacus without the slave narrative, as his armies would terrorize Rome in a similar way. The Punic War would also create an opportunity for some massive onscreen battles.
Casting Choice: Tom Hardy has played some of the most imposing characters in recent screen history in Bane and Charles Bronson so he would definitely bring the intimidation factor.