Description - When you are attacked with a melee attack, you use your reaction to increase your Armour Class, potentially causing the attack to miss.

This doesn't indicate how much your AC is increased or what influences the amount of AC increase.
Assuming this is following 5e rules, this would add your proficiency bonus to your AC when you use your reaction. This being vague and unexplained doesn't make it clear exactly what this feat does for a player.

Last edited by cptmuffins; 10/10/20 03:38 PM.