The Immortals are the Zoroastrian holy order, available only for Zoroastrian rulers, once the Persian empire is restored. Like all holy orders, they are hired with piety, and only fight against heretics, rebels, and those of other religions, free of maintenance costs in case of fighting the latter.
Historical Information Edit
Historically, the Immortals were the standing army elite guards of the Achaemenid Empire (550–330 BCE), only ethnic Persians and Medes were allowed into their ranks, and formed the mainstay of the Persian Army when the Empire waged war.
They were the best equipped and trained warriors of their time, skilled at long and close range, expected as a whole to be proficient at every way of combat, excelling as bowmen and spearmen, with both infantry and cavalry regiments. Known for numbering exactly 10,000 men, every man fallen in battle by injury, disease or death was immediately replaced, maintaining impeccable cohesion and discipline, hence the nickname "Immortals" given by their Greek enemies. They play a big part in Persia's invasion of Greece, in particular the Battle of Thermopylae, where after the heavy casualties of the regular levied army, the Immortals fought an evenly matched fight against the famed Spartans and their allies.
A similar institution was formed by the times of the Sasanian Empire (224–651 CE), consisting of bravest and most skilled crop of the strongest Imperial military forces: Heavily armed elite knights.
During the late 10th century, the Byzantine Empire formed an elite heavy cavalry unit named after the Immortals of old, of similar prestige to the Varangian Guard, even competing with this famous unit for the Emperor's favor in some instances.