s reen indicates the stren th of your Magic Shield. The Magic Shield protects the army from enemy spells, preventing them fro m taking effect if the shield is strong enough.
Spells have a penetration value, from Low to Very High, if a spell has a higher penetration value than the current shield strength, it will come into play normally, taking full effect. Spells with equal or lower penetration value than the current shield strength will be completely absorbed, damaging the shield instead.There are several game elements which can alter this balance, by increasing the rate at which the shield regenerates, the penetration values of spells, and other means.
Each Army has its own Magic Shield rating, which receives it's sum from all Skills and Artifacts possessed by all Heroes in the army, though the total is only displayed in the Main Heroes' character window.
There are four levels of Shield Resistance, designated by the four shields, achieved at shield levels 20, 40, 60 and 80, and protecting against Low, Normal, High and Very High penetration spells, respectively.
Magic Shields have a maximum numerical value of 105, although 80 is the minimum practical amount you need for Very High resistance, anything more will serve only to buffer your shield.
A rating between 0-19 will protect you from nothing.
20 – 39 will give you the first shield on the bar; Low resistance, and protect you from Low penetration spells. Normal and higher penetration spells will come into play, with no effect on your shield.
40 – 59 will give you the second shield on the bar; Normal resistance, and protect you from Normal penetration spells. High and higher penetration spells will come into play, with no effect on your shield.
60 – 79 will give you the third shield on the bar; High resistance, and protect you from High penetration spells. Very High and “Always Penetrates” spells will come into play, with no effect on your shield.
80 – 105 will give you the fourth shield on the bar; Very High resistance, and protect you from Very High penetration spells. Only “Always Penetrates” spells will come into play.