Resistance
Resistance is a secondary skill that increases the magic resistance of hero's troops. Warlocks, Witches and Wizards cannot learn Resistance.
Heroes with Resistance as a starting skill:
Ajit the Overlord - Basic Resistance
Bron the Beastmaster - Basic Resistance
Clancy the Ranger - Basic Resistance
Fafner the Alchemist - Basic Resistance
Ignatius the Demoniac - Basic Resistance
Krellion the Barbarian - Basic Resistance
Saurug the Battle Mage - Basic Resistance
Straker the Death Knight - Basic Resistance
Thorgrim the Ranger - Advanced Resistance
Ufretin the Ranger - Basic Resistance
Zilare the Navigator - Basic Resistance
Heroes with a Resistance specialty:
The following heroes receive a 5% per level bonus to their Resistance skill.
Horn of the Abyss
In Horn of the Abyss, Resistance since v.1.6.0 is banned by default, and all heroes that would start with Resistance start with Interference, aside from Thorgrim, who is also banned by default.