|Unit Information||Game Strategies||History|
| In the Extended Edition, this unit/building is affected by a damage bug.
However, Immortals have the very special advantage of a ranged attack, with a range equal to that of the standard Light Infantry line, and faster projectiles (100 compared to Light Infantry's 80), being the only Heavy Infantry to have this capacity before the Gunpowder Age. Being ranged has a disadvantage, however; unlike Hoplites, Immortals lack the 80% damage bonus against Supply Wagons that melee units have.
Their ranged nature, combined with higher speed, make Immortals excellent for hit-and-run tactics against enemy Heavy Infantry, and gives them a significant edge in combat against them, as they can inflict plenty of damage before the enemy can close in and engage (if they manage to engage in the first place), more than compensating for their slight disadvantage in damage and toughness; these strengths also make Immortals particularly tough raiders and even more deadly to enemy Light Infantry than other Heavy Infantry units, and are the best choice for Ancient Age rushes.
- The unit has a specially-coded melee attack animation to use when in melee range, which it loses when upgraded to Anusiya or any later unit. Beyond being undodgeable (due to not using a projectile in any capacity) and having less animation variance, the attack is functionally equivalent and deals the same amount of DPS as the unit's standard ranged attack (including against Supply Wagons).
- Immortals, along with Anusiya and Athanatoi, are the only Heavy Infantry to have a ranged attack without a gunpowder weapon.
- Immortals are based on the historical elite heavy infantry unit of the Achaemenid Persian Empire, popularly known by the same name.
- Although the ranged capabilities of the Immortals compared to contemporary heavy infantry of the period has an historical basis, in reality this was due to their dual capability as bowmen and spearmen, not as javelineers depicted in-game.
- The "leopard skin" seen on the Immortals' dipylon shield is a recurrent theme of the Persians' unique Heavy Infantry, although this striking pattern has no historical basis.