Crucible of Might

More than any other barbarian, your rage is tempered by a defensive nature, yet your strength and ability to exploit weight are unparalleled. Starting at 3rd level you gain proficiency in heavy armor, and can use all barbarian class features while wearing it, even if those features state otherwise.

You can wield any melee weapon with the versatile or two-handed property in one hand as though it were held in two, though you cannot use two-weapon fighting with weapons that you wield in this way, and you must your Reckless Attack feature in order to attack with them in this way. If your size is Small, you can wield a weapon with the heavy property without penalties. Finally, you gain proficiency with smith's tools, and can produce armor and weapons twice as quickly.

Unyielding

Starting at 6th level, your armor's weight lets you barrel through obstacles. While you wear heavy armor, you can move through difficult terrain and effects that require you to spend additional feet of movement such as the wall of thorns spell without being slowed. In addition, when you are subjected to an effect that would move you, knock you prone, or both against your will, you can use your reaction to ignore the effect.

Iron Curtain

At 10th level, the bulk of your mighty armor forces enemies to work around your presence, distracting them from harming your allies. When a creature within 5 feet of you takes nonmagical bludgeoning, piercing, or slashing damage, you can reduce the damage taken by an amount equal to your armor's damage reduction, if any.

Dreadful Dreadnought

Starting at 14th level, your ability to shrug off mighty blows demoralizes your enemies, which reduces the impact of their subsequent strikes. Whenever you take an amount of bludgeoning, piercing, or slashing damage less than half your barbarian level, the creature that inflicted that damage has disadvantage on the next attack it makes against you, before the end of its next turn.

 
Dark Souls: Iron Knight Tarkus, karniz