The Army of Anubis was an ancient legion of the Underworld which acted out under the command of Anubis, engaging opponents in battle and laying waste to cities.
Magus, a loyal student of Anubis' teachings gained control of Anubis' Army of jackal-headed humanoids thanks to his belief on sacrificing a human to bring about Set and crush the land of the living. Once Magus died at the hands of a warrior named Mathayus, the army disappeared.
The Invasion of Thebes
Years later, Mathayus, now known as the Scorpion King, led a great army across the deserts to conquer Thebes, but lost despite the battle that he and his warriors carried out. The Scorpion King and his armies were expelled out into the deserts of Ahm Shere, where one by one the warriors all died due to heatstroke, exhaustion, hunger and thirst, leaving the Scorpion King the sole survivor.
In his dying moments, Mathayus prayed to Anubis; in exchange for his life and the chance to once again be a conqueror, the Scorpion King pledged his soul and a pyramid of gold. In response, the Scorpion King was presented with a large black scorpion which came crawling from the sands; Scorpion King promptly picked the arthropod up and chewed it down as food, accepting the favour that Anubis had bestowed. From the sands sprouted a great oasis which would come to be known as the oasis of Ahm Shere. With this, the Scorpion King was also given command of his new master's immortal army where his human troops once stood; he now proceeded to use them to lay waste to the city of Thebes. Anubis then forced the Scorpion King to become his eternal servant as part of the bargain, turning him into a monstrous scorpion beast and returning the Army of Anubis to the sands from whence they came.
The Scorpion King succeeded in destroying the city of Thebes, but was then dragged to the Underworld and mutated into an unholy creature by Anubis himself, and the Army was ordered to return into an infinite slumber. The legend went on from that time forward that every 5,000 years the Scorpion King, along with the Army of Anubis, would awaken to once again attempt to destroy and conquer civilization. Whoever could kill the Scorpion King with an ancient golden spear known as the Spear of Osiris could decide whether to use the Army of Anubis to conquer the Earth or send the Scorpion King and his forces back to oblivion.
5,000 years later, in the year 1933 AD, archaeologists Rick O'Connell and Evelyn O'Connell, along with their son Alex discovered the Bracelet of Anubis, which was once worn by the Scorpion King, in an ancient temple and the key to unlocking and reviving the Army, after nearly being drowned in a flood inside of the temple that was instigated by three thieves, Spivey, Red and Jacques. Upon his family's return to England with the Bracelet so as to further study it, Alex surreptitiously put on the bracelet, unaware that he now would have seven days to reach the Golden Pyramid of Ahm Shere in order to confront the Scorpion King and remove the Bracelet.
Alex was soon after kidnapped by a cult that worshipped and resurrected the cursed mummy Imhotep, so as to have Imhotep defeat the Scorpion King. The boy’s parents went on a quest both to rescue Alex and to beat Imhotep to Ahm Shere before he might slay the Scorpion King and take command of the Army. With the goal to reach the city first and either avert destruction or accelerate it, both groups, the cultists and the archaeologists made off in hot pursuit of the oasis of Ahm Shere. The O'Connells sought the help of the warrior Ardeth Bay, who enlisted the warriors of the Medjai, an ancient secret society dedicated to the protection of mankind, to journey through the deserts to reach Ahm Shere and battle the Army of Anubis.
It was not long after both parties had reached the great oasis of Ahm Shere and the evil Bracelet finally removed from Alex's wrist that the cult's leader Baltus Hafez had found the Bracelet of Anubis lying in the sands inside the pyramid, put it on, and inserted his arm wearing the Bracelet into a hole inside a giant scorpion statue within the Gold Pyramid. Instantly the entire Pyramid was bathed in light, and restored to its former condition from 5,000 years back. With this change, a massive scorpion-shaped shadow fell across the desert outside the Oasis, where the Medjai army, knowing what would come next, was gathered to face the undead warriors.
The Battle for Ahm Shere
The shadow caused the sands which it touched to become an ashy, tar-like substance, regenerating the soldiers of the Army of Anubis, which congealed slowly from the ashes and morphed into jackal-headed humanoid mummies; the Army engaged the Medjai in battle.
However, the Anubis warriors were easily killed by decapitation, and were soon slaughtered. Ardeth Bay, the Medjai chieftain, noticed the odd ease of their victory, and after hearing a rumble from ahead ran to the top of a dune, along with his men to see a mammoth, never-ending army of Anubis warriors, stretching off into the distance; the force they had just defeated was only the vanguard, and now the main army was bearing down on them, too immense for the Medjai to have any hope of defeating.
Just as the bloodthirsty army was about to collide with the brave yet outnumbered Medjai, Rick O’Connell succeeded in killing the Scorpion King back in the pyramid, ordering the Army to instantly return to the Underworld. In an immense blast of black sand and ash, the Army of Anubis dissipated into thin air, and the saved Medjai called out with relief and triumph at the final ending of the evil Army.
The Army of Anubis was made up of thousands of nine foot tall muscular humanoids with heads that resembled that of jackals. Many wore a headdress similar to that worn by ancient Egyptian pharaohs as well as golden armor and jewelry, some wearing piercings. Equipped with razor-sharp teeth, armed with double-bladed-edged axes and spears, and able to run at incredible speeds, the jackal-beasts craved blood and violence, fearing nothing. When they were raised in modern times, they appeared to have mummifed bodies and took a much more skeletal look, most notably in the chest.
Warriors in the Army could only be killed by decapitation, and could not be defeated or destroyed entirely unless their heads were removed, at which point they instantly reverted to black sand, dissipating. Their numbers were such that a great and numerous legion of them were sent out at the Medjai confronting them in 1933, and were taken down shortly after being replaced with a substantially larger number of Anubis warriors. The warriors could be eviscerated by an edged weapon but suffered no pain, though their movement would be affected were they to lose limbs, as one was hindered after losing a leg by Medjai's blade.
Behind the Scenes
The Army of Anubis was generated entirely with the use of computer graphics.
In the technical commentaries for the deluxe edition of The Mummy Returns, it is mentioned that in the battle, 32,000 animated warriors were present. But according to other sources, 64,000 warriors were present in their second appearance in the film.
If these statements are accurate, the total amount of warriors is brought to 96,000. A far cry from Ardeth Bey's (most likely hyperbole-laden) assertion that the army had as many members as the Sahara Desert had grains of sand, but still not a force to underestimate.