Magic resistance is a special ability of certain creatures, which grants them a chance to resist hostile spell effects. Magic resistance does not mean that the creature is immune to spells, and unlike with spell immunity, they can be target of any spell.
Magic resistance of creatures can be increased with Garniture of Interference, Surcoat of Counterpoise or Boots of Polarity artifacts. Contrary to artifacts like Bow of Elven Cherrywood, the hero wearing artifacts that increase magic resistance, doesn't need to have Resistance secondary skill in order of them to work. Although, with Resistance skill a hero further enhance the magic resistance of his troops.
Creatures with magic resistance special ability:
* Unicorns and War Unicorns do not technically have magic resistance themselves, but they project an aura of magic resistance to adjacent hexes.