Path of Iron

NOT MY SUBCLASS -- Full credit to u/The_Palm_of_Vecna on r/UnearthedArcana -- Though, I slightly adapted the Riddle of Steel feature. Feel free to ignore it and just use the original feature description.

 

Rage burns in every barbarian’s heart, a furnace that drives him or her toward greatness. Different barbarians attribute their rage to different sources, however. For some, it is an internal reservoir where pain, grief, and anger are forged into a fury hard as steel. Others see it as a spiritual blessing, a gift of a totem animal.

Of all the innovations man has made over the years, one would be hard-pressed to find a more significant invention than steel. With the discovery of steel, man gained a nearly unparalleled ability to carve his way into the world around him, and through the beasts and enemies that held him at bay from the darkest reaches of the world. To a barbarian of the Iron, steel isn't just what he shapes into his weapons and his armor, it lies in his very heart and soul.

Iron Frenzy

You excel at fighting in the heaviest armor and while using the heaviest weapons, leaning to use their weight to your advantage.

At 3rd level, you gain proficiency in heavy armor, and you may gain the benefits of Rage while wearing heavy armor. Additionally, while raging, once per turn you may deal an additional 1d4 damage with a melee attack from a heavy melee weapon.

Juggernaut

You are an unstoppable force, and no creature can impede you from your chosen path.

Starting at 6th level, you may benefit from your Fast Movement bonus speed while wearing heavy armor, and you are considered 1 size category larger for the purposes of shoving and moving through a hostile creature's space. If you move at least 10 feet in a straight line before attempting to move through a hostile creature's space, you do not treat that space as difficult terrain, and you do not provoke an opportunity attack from that creature.

Starting at 14th level, you are considered 2 size categories larger.

Riddle of Steel

Crafting and metalworking are in your heart, your blood, and your soul.

At 10th level, you gain proficiency with smith's tools, and while crafting armor or weapons, you make progress at a rate of 50 gp per day. Your gp progress rate increases based on your level and Intelligence modifier (min. 0) as your greater intellect and experience allow you to craft with greater efficiency and to make fewer mistakes. 

 

Iron Giant

Though massive, your armor and weapons are but tools for your greatness; it is you who is larger than life.

Starting at 14th level, while wearing heavy armor and raging, you gain the Enlarge effect of the enlarge/reduce spell, though it is not a magical effect and cannot be dispelled. This effect ends when your rage ends.