AC Redefined; Re-imagined

AC is the numerical value for the defence of any character, be they player or NPC. When an attacker lands a successful hit on a target, the damage first goes to AC. AC must drop to 0 before the target takes any damage to HP. AC stands for both Armor Class and Aura class.

Every living thing has an aura. This aura provides a measure of protection. Armor and aura combine to provide a character's  AC. In this way, a defender has a measure of protection from attacks of both the mundane and arcane variety.

When AC drops to zero, the armor and/or aura breaks. Armor can be repaired through the methods in the crafting rules section, and spells like the cantrip Mending, and auras can be restored by recasting spells like Mage armor. Otherwise, the aura is restored through taking a long rest.

There are items, spells, and skills that allow for auras  to be harvested. These Auras can then be infused in armor and other items to provide an additional level of protection, and add special properties.