Summary
Some classes will grant an innate damage mitigation bonus to your character. The maximum bonus a character can have is 30%.
Details
Warrior - 15%
Paladin - 10%
Shadow Knight - 10%
Beastlord - 7.5%
Monk - 7.5%
Ranger - 7.5%
Bard - 5%
Berserker - 5%
Cleric - 5%