Attila is a cavalry hero found only in the The Scourge of God and The Fall of Rome scenarios of his campaign, as well as in the Scenario Editor. He appears as a Cataphract. He is a must-survive unit in both of the scenarios, and in the latter, he must meet Pope Leo I outside Rome to win the scenario. As a hero, he cannot be converted and can regenerate health.
Despite being a cavalry unit, before the Definitive Edition, Attila was assigned to the infantry armor class, and thus took no bonus damage from anti-cavalry units such as Pikemen and Camel Riders. He could also garrison inside rams, while other cavalry units cannot. In the Definitive Edition, after certain updates, Attila is now in the cavalry armor class and cannot be garrisoned inside rams.
In the Definitive Edition, Attila has a new, unique sprite similar to a Tarkan but armed with a curved sword instead of a torch. The curved sword is historically inaccurate; Huns wielded straight, double-edged swords.
|“||Barbarian hordes feast on the dying Roman empire. The most dangerous of these invaders are the Huns and their ferocious king, Attila. After pouring out of the Caspian steppes, looting and burning all the while, the Huns become so powerful that the Roman Empire is forced to pay a tribute to Attila. But the king of the Huns is still not satisfied, and he mobilizes his horsemen to invade Gaul and eventually Rome itself! Can nothing stop the brutal Attila?||”|
|—In-game campaign description|
The Attila the Hun campaign consists of 6 scenarios. The player plays as the Huns, and the player color is yellow.
- The Scourge of God
- The Great Ride
- The Walls of Constantinople
- A Barbarian Betrothal
- The Catalaunian Fields
- The Fall of Rome
Unlike other campaigns, the story is told not by a witness of the events but by a second-hand narrator, an unnamed Frankish monk from a monastery near Chalons, who is relaying them as told to him by his superior, an old priest named Armand. The cutscenes reveal that, as a young man, Armand fought on the Roman side at the Battle of the Catalaunian Fields (451 A.D.), but that he defected to the Huns after being captured by Attila, and fought by his side on the following invasion of Italy.
- This campaign takes place entirely before the traditional start of the Middle Ages at the fall of the Western Roman Empire in 476 A.D. It was both the only non-anthology campaign set before 1000 A.D., and the earliest chronologically until it was beaten by the Alaric campaign in Age of Empires II HD: The Forgotten.
- The possibility of an Attila campaign was a determining factor in Ensemble Studios's decision to introduce the Huns as the new Central European civilization in The Conquerors, instead of their likeliest alternative, the Magyars.
- During the campaign, the player fights against several Italian cities variously represented by Teutons, Britons, Celts, and Byzantines, due to the Italians not being introduced until The Forgotten. None of them are changed to Italians in the Definitive Edition.
- Attila's two proposed years of birth coincide with key dates in the timeline leading to the Fall of Rome: 395 A.D. was the year when the Western and Eastern Roman Empires split for good, and 406 A.D. was when the Vandals, Alans, and Suebians crossed the frozen Rhine to invade the Western Empire.