Resolve Of The Battle Mage

Tempering your defenses in battle, you have learned to utilize your spells to stand your ground. You gain the following benefits while wearing heavy armor:

• Increase your Constitution score by 1, to a maximum of 20.
• When you cast Mage Armor on yourself you gain a +2 to your AC instead of the normal effect.
• Once per short or long rest, you may reduce damage taken by expending a spell slot. As a reaction when you take damage you can expend a spell slot to reduce damage by 10X the level of spell slot used.