Path of the Asura

Though the paths they take seem to be disparate, each of these barbarians follows the primal Path of the Asura, tapping into a special, inner strength which heightens their physical ability. Many Monks believe these barbarians to be unlocking the secrets of Ki, using it crudely to boost their performance, although some monasteries cultivate and train these barbarians for that purpose. Some of these barbarians believe that instead, they have inherited the might of Giantkind, their titanic strength born of those mighty beings, though whether these claims are genuine or not is up to debate, especially among Giants. Other barbarians think that they've merely broken the limit of what their bodies can accomplish, or feel they've been bestowed divine power by a God of Strength, while others don't know or care for the source of their strength at all. Regardless of where these barbarians find this power, anyone can agree that those down this path are pugilists without equal, whose fists strike with the power of steel and can fell even the strongest of foes.

Iron Body, Iron Fists

Starting when you choose the Path of the Asura at level 3, you learn a style of martial arts dependent on your physical toughness. When you make an unarmed attack, you may roll a d6 in place of the normal damage of the unarmed strike. The damage die increases as per the monk martial arts die (1d8 at Lv.5, 1d10 at Lv.11, 1d12 at Lv.17). Additionally, while raging, you may make one unarmed strike as a bonus action when you take the attack action in combat.

You also gain resistance to poison damage while you are raging as part of your body being strong as iron

Raging Ki

Starting at level 6, your intense rage stirs the dormant ki inside your body, sending it to the surface. Whenever you rage, you may treat your unarmed strikes as magical weapons for the purpose of overcoming damage resistance.

Battle Focus

Level 10 - Battle Focus
At level 10, your intense rage allows you to focus your mind during combat, blocking out distractions. While raging, you have proficiency advantage in Wisdom saving throws.

Retaliation

Starting at 14th level, when you take damage from a creature that is within 5 feet of you, you can use your reaction to make a melee weapon attack against that creature.