The Ptolemaic Army is the villainous group in Metal Slug 5. They are an armed guerrilla formed by mercenaries and special agents, having a full arsenal of weaponry and sophisticated machines under their disposal, which includes an assortment of combat mechas. However, the Ptolemaic Army is founded and commanded by the members of a mysterious cult of masked shamans called the "Ptolemaics" at the core of the Army, who worship an ancient demon known as the Evil Spirit Incarnate, and seek to achieve world domination by bringing this demon back into our world.
To help further this goal, their agents infiltrated the Regular Army headquarters and stole a disk containing data about the latest generation Metal Slugs, as well as many other vehicles used by the Regular Army and the Rebel Army. Using this data, they created their own variations of the Metal Slug, which included a gigantic sized Metal Slug and the Black Hound, which was an enhanced Metal Slug in all aspects.
Treating the incident with utmost urgency, Regular Army HQ orders the P.F. Squad and S.P.A.R.R.O.W.S. soldiers to follow the tracks of the Ptolemaic Army and stop whatever plan they have in mind. The conflict ended with the demon being defeated. However, it flew away before it's true identity could be revealed. The Ptolemaic threat seemed to be at an end.
The Ptolemaic Infantry are a militant arm of the Ptolemaic Army. Skilled and dangerous, Ptolemaic soldiers within the infantry are seen as a "Special forces" unit. Their weapons are more advanced than those used by the Rebel Army
- The Ptolemaic Army's original name came from the adjective formed from the name of Greco-Egyptian 2nd-century AD geographer and astronomer/astrologer Claudius Ptolemy. That name also became part of Ptolemy I Soter of the Ptolemaic Dynasty which founded and ruled the Ptolemaic Kingdom in 305 BC, of the citadel known as the Ptolemaic Baris (also known as Ptolemaic Acra), and of the Ptolemaic system.
- They appear to be based on the Brotherhood of Nod from the Command and Conquer series due to their combat styles, as well as real life Illuminati/Freemasonry secret societies given their pseudo-religious nature.
- If the Ptolemaic Boss is their leader, then the Plotemaic army could be the native enchance the intelligents because of the mask they wear, but in the battle, he does not have a mask, that gives that they may summon the Evil Spirit Incarnate to the world as their great demonic leader. But if it is their leader, then the Ptolemaic Boss may have turned into a demon in the final battle wanting to end the characters' disturbances into their success.
- They have original ideas but instead steals ideas from the S.P.A.R.R.O.W.S, the Regular Army and the Rebel Army the enchancing to make a bit different and more powerful.
- All shamans have the same attack and health, they only have hood colors to show their ranks.
- In the revised version of Metal Slug 5, the Guerrillas and Special Forces have a color variant.
- There is an alternate flag of not only the Ptomelaic Army but also the Rebel Army that only somewhat resembles the Evil Spirit Incarnate, but also is loosely based on the secret Nazi doomsday plan called Project Ragna Rok from the Hellboy comicbook series whose other name called "Fatal Destiny" can be translated with the words both "Tödlich" ("Fatal") and "Schicksal" ("Destiny") in German, and both "Skjebnesvanger" ("Fatal") and "Skjebne" ("Destiny").