Magic resistance
Magic resistance refers to creatures' ability to resist spell effects. Dwarves and battle dwarves have natural magic resistance against spells. unicorns and war unicorns do not themselves have a magic restince, but they create an aura of magic restiance that they project to adjancet hexes.
With Garniture of Interference, Surcoat of Counterpoise or Boots of Polarity artifacts, a hero can gain magic resistance to all allied creatures.