Magic Resistance

Magic Resistance is an attribute of heroes, extremely similar to Armor. Instead of reducing physical damage, it reduces magical damage. All heroes possess 25% Magic Resistance from their armor type. This percentage is completely independent of their amount of Armor. Certain hero summons, such as Enigma's Eidolons, also possess intrinsic magic resistance.

Magical Damage
Magical Damage is a special damage type caused mostly by spells. Unlike Physical Damage, it isn't reduced by Armor. However, it is reduced by Magical Resistance, and will not effect targets that are Magically Immune or Buildings that are fortified. Ethereal units will also take 40% amplified Magical Damage.

Mixed Damage is similar to Magical Damage. It is reduced by Magical Resistance and Armor, but ignores Magic Immunity. Mixed Damage does not affect Ethereal units.

Damage Reduction/Increase
All Heroes have a natural 25% Magic Resistance. This means that, by default, all magic damage is reduced by 25%, or only 75% of the spell's damage. Any additional effects, such as the bonus given by Hood of Defiance, will reduce the remaining damage by their resistance.


 * Spell Damage × ( 1 − 25% Natural Resistance ) × ( 1 − Magic Resistance of Item ) × ( 1 − Magic Resistance of Abilities ) × ( 1 + Magic Amplification ) = Actual Damage

Items that increase magic damage (such as Veil of Discord) multiply their effects on the end of this equation. Therefore, the maximum magical damage that can be done is 94% a spell's damage.

Magic Resistance Items do not stack. Therefore, only the last Item that grants Magic Resistance will provide a bonus. Stacking Magic Resistance (from Items, Abilities, and naturally) occurs multiplicatively. For example, an Anti-Mage with Spell Shield, and Hood of Defiance will have 73.75% Magic Resistance.


 * 1 − ( 1 − 25% (Natural) ) × ( 1 − 30% (Hood of Defiance) ) × ( 1 − 50% (Spell Shield) ) = 73.75% Magic Resistance

Skills and Items that Grant Magic Resistance