In a DnD game I played, my friend caught me off guard and i was surprised with the explanation I was given. So it was me(Sorcerer-Knight) and a few friends such as Lolana the Vampire Siren(Healer), Vos Possidebitis the Living Sword that possessed whoever wielded them(Rogue), Ackeeve the Half-Orc Archer, Evil King as the Dungeon Master, and finally Bruticus (he was a Transformers fan) the Barbarian. So we started off in a swamp where we had to kill these creatures that had the front of a crocodile and the back of a snake. Me, being the one to be surprised attack, nearly died the first 5 minutes of the campaign but what surprised me even more was that Bruticus was more damaged than I was. I let it go thinking it was nothing and we headed to an old village and was able to get a lot of money for the creatures we killed.(Apparently we killed the creatures before we were supposed to and was going to be given the quest when we got to the village) Though this campaign in almost every battle Bruticus is wounded to near death even when he is able to kill enemies in one hit if he gets a Nat 20. I ask him "Why do you always has such bad injuries after every battle?" He replied "I'm letting them injure me on purpose." This confused everyone and we all asked "why?" except for the Dungeon Master. He told us to "wait and see" and that made everyone in the party worry. We get on with the campaign for a few more days and Bruticus is still doing the same thing but I was the only one noticing that every day he was taking off more and more of his armor. We get to the final day of the Campaign and we get to the door before we were to fight the Evil King. Before we entered the Throne room we all put on our best gear, equiped our best weapons and scrolls, and had our potions at the ready. I equipped a set of armor made from cosmos ingots and a sword that can do energy slashes, Lolana put on her seduction armor and a bladed fan, of course Vos was using them self as their weapon and equipped a set of dragon armor(which irked my character seeing as how I was the reincarnation of the King of the Draconian Species) , Ackeeve equipped an enchanted plant armor with a magical bow that can shoot lightning, and finally there was Bruticus who had the Bloody-Skull Ax but he put on his armor from the beginning of the campaign. We all thought he lost it and before we could get any objections in he swung his ax shattering the door and walked into the throne room. The Evil King was accompanied by two Necromancers that were very annoying. We dispatched the Necromancers easily but at a great cost. When a necromancer died they exploded with "soul energy" (still don't think that was fair) and we had to roll above 15 to survive. All of us failed the roll, all of us took critical damage, all of us was one attack away from being dead, except for Bruticus. He stood before the Evil King and looked into those black ,abyssal eyes. The evil king laughed at him and told him "You think you can challenge me? Me? In the pelt you call armor? I can kill you with a single swing of my sword!" "Then do it" Bruticus replied with a grin on his face. The rest of the party thought he had given up and forfeited the campaign , while I was just confused. The Evil King was outraged and swung his claymore at Bruticus and right before the ax finally hit, the DM said roll initiative and everyone else had a dumbfounded look on their faces. Bruticus rolled a Nat 20. We thought that meant he would dodge ot the he secretly knew how to teleport but no, Bruticus stood absolutely still. When the claymore finally hit him, "It shattered from hitting your nearly impervious skin." and we couldn't believe it. The entire time he was allowing himself to get severely wounded was to make his skin his armor. After that we used potions to heal ourselves and easily beat the Evil King but that's not all. When I asked him how this was possible, he said, “Think of all of my outer layers of skin became calloused and that my dense muscles as shock absorbers”. I never looked at barbarians the same way again.