Armor is Value that some units have. This is an added defense for that unit. Armor in its fullest form will block no more than 90% of Damage. THE ANTI-ARMOR VS. ARMOR CALCULATIONS ARE THE FIRST MADE IN COMBAT
So a Unit with 7 Armor and a unit with only 1 Armor will BOTH block 90% of armor as long as they have full armor.

Now to deal more damage to this unit you must deplete or at least damage that Unit's/Units' Armor.
When a unit loses armor it takes more damage. If the unit with only 1 armor loses its only armor it will take full damage from all attacks made against it.

The equation for armor is both simple and not.

Armor protection = (armor remaining after strike/ Total Armor)X90%)

this means if a Julian gets attacked with 2 anti armor the equation would be
(5/7)X0.9) which = 0.64285714285714285714285714285714
Now I think REIIGN only calcs out 2 decimal places so that would be 64%
So during that strike, the Julian is immune from 64% of the total attack against it.

A units armor will only regenerate once the entire battle is concluded.
so the more strikes a unit is in the more its Armor is drained and the more damage it will take.


ANTI-ARMOR

Anti-Armor is a value that all but the snipers have. This anti-armor value is used against enemy armor values.
in the same way normal attack value drains enemy HP. Anti-armor drains the enemies armor. THE ANTI-ARMOR VS. ARMOR CALCULATIONS ARE THE FIRST MADE IN COMBAT.

When a unit is used to attack its anti-armor is as stated in the production panel, and deals such damage to the enemy. However, when attacked, A unit's Anti-armor value IS affected by YOUR DER% if you have less than 100% DER your anti-armor Defense is gonna be reduced and increased if over 100% up to 5 times its normal value.