Blood Shield

You have become so familiar with pain that you can use even the gravest of wounds to your advantage. When you are hit by a spell that deals damage to you, you can use your reaction to draw the blood from your wounds to shore up your armor and protect yourself. You take damage as normal, but you gain resistance to that type of damage for the duration of the spell. For every 10 points of damage you take, your AC increases by 1 (minimum of 1). Each subsequent round, at the beginning of your turn, your AC decreases by 1 until it returns to its original stat, at which point the spell ends.