As stated by the title, getting high enough armor will cause you to be healed by attacks. More specifically, equiping a full suit of armor made primarily from Elven Metal paired with the trait for +5 armor gives you a total of 105 armor, at which point you heal for what seems to be 5% of the damage that attack would deal with no armor. I assume the backend code is something like Actual Damage = Base Damage x (1 - (Armor / 100), and just needs a check to make sure Actual Damage is never less than zero, though I could be wrong.