Their specialties are espionage, sabotage, guerrilla warfare, incursions, wizardry, and dark magic.
Their sect-like structure and the great amount of cultists and wizards in their ranks seems to confirm this. Despite their technological capabilities, they are presumably trying to achieve their goal through the use of supernatural forces, given their large involvement in mysterious practices. The Ptolemaic Army's motives are unclear but are likely centered around world domination and eventual subjugation of all reality and timelines to their Dark Lord.