Path of the Barefoot Brute

You are a halfling of both unusual temperament and strength. You favor the use of weapons designed for creatures much larger than yourself, and have learned not only to wield them, but to wield them with unrivaled agility in ways only your smaller stature allows.

Restriction: Small Creatures Only

This subclass is restricted to races with the small size.  Though this was originally designed to be a Halfling specific subclass, it is available to any/all small sized barbarians.  

Dance of Flesh and Steel

Having spent countless hours hauling around a weapon that is nearly as big as you, you have become the pinnacle of halfling strength and agility, learning to wield large weapons using unusual forms fit for your stature. Starting at 3rd level, you gain the following benefits:
- Proficiency with the Athletics skill. If you are already proficient, you can double your proficiency bonus when using Athletics. This doesn't stack with similar abilities.
- While wielding a melee weapon with the Heavy quality, you no longer have disadvantage due to your size.
- While Raging, you can add your Dexterity modifier to weapon damage rolls you make with Heavy, Two-Handed melee weapons, in addition to your Strength modifier.

Knee Capper

You take full advantage if your small stature to confound and assault larger foes. Starting at 6th level you can move through the space of any creature that is larger than you and not treat their space as if it were difficult terrain.

Additionally, while raging, if you attack and hit a creature with a melee weapon attack using a heavy weapon after moving through their space, that creature must roll a Strength saving throw with a DC = 8 + your proficiency + your Strength modifier.  On a failed save, they are knocked prone.

Reckless and Wild

Your halfling nature is emboldened by your great strength and exploits.  Starting at 10th level, you are immune to fear effects. You also gain proficiency with Dexterity saving throws.

Violence of Action

Your rage is spontaneously dangerous, and you waste no time in a fight. Starting at 14th level, when you use your bonus action to start raging, you can use your action to double your movement speed and make up to five melee attacks. Each attack must be made against a different creature.

You must complete a short or a long rest before you can use this ability again.