Armour Class (or AC) is what protects you from Attacks, or the numbers you need to beat in order to successfully hit your enemies. Various equipment such as Armors and Shields can provide bonuses to your Armour Class, decreasing your chances to get hit.
- Determining your base Armour Class:
10 (Natural Armour Class) + Dexterity Modifier - In order to successfully hit enemies, your Attack Roll must have a number equal or bigger than the number of the target's Armour Class.