There are five damage types with Elemental resistances to them: Fire, Shock, Cold, Acid, and Poison.

These directly deduct from the hit landed on the target with them; the amount deducted is equal to the point value of the resistance, plus 2% of the remaining total for each point. For instance, a unit with 5 Fire Resistance also takes 10% less fire damage beyond that. A unit with 50 points in a certain resistance is thus immune to the damage type the resistance addresses.

Elemental Vulnerability deducts from Elemental Resistance, and vice-versa.