Path of the Iron belly

While some barbarians rely on fast reflexes or supernatural agility, those who follow the Path of the Iron belly simply don't care to move out of the way. These warriors are titans of muscle and girth. They possess an unbelievable physical density. They treat incoming weapons like minor inconveniences, absorbing lethal strikes into their massive frames and converting that kinetic energy into devastation counterattacks.

Level 3: Dense Frame

Your sheer mass and thick layer of muscle and fat protect you better than any armor can.

 

Gargantuan Girth

You count as one size larger when determining your carrying capacity and the weight you can push, drag, or lift. Additionally, you have advantage on saving throws and ability checks against being moved or knocked prone.

Thick fat

While you are not wearing armor, your Armor Class equal 10 + Str + Con. (You can still use Unarmored Defense if you choose)

Level 3: Kinetic Absorption

When you take damage while raging (except from Psychic, Radiant, and Necrotic sources), you store a portion of that energy as ADIPOSE CHARGES. You gain a number of charges equal to your Constitution modifier (minimum of 1). You can hold a maximum number of charges equal to 2x your Barbarian level. All stored charges vanish when your rage ends.

Once per turn, when you hit a creature with a melee weapon or unarmed strike that uses your Strength modifier, you can expend any number of stored charges to deal 1d4 force damage per charge expended.

Level 6: Unstoppable Momentum

As a bonus action, you can dash in a straight line. During this movement, you can pass through the space of any creature your size or smaller.

Each creature whose space you pass through must make a Strength saving throw DC = 8 + proficiency bonus + STR.

On a failed save, a creature takes bludgeoning damage equal to 1d12 + STR and is knocked prone. 

On a successful save, a creature takes half damage and is pushed 5ft to an unoccupied space of their choice out of your path.

You can use this bonus action a number of times equal to your Constitution modifier (minimum of once), and you regain all expended uses when you finish a long rest.

Level 10: Forceful Blows

When you make a melee weapon attack or unarmed strike while raging, you can expend up to half of your maximum ADIPOSE CHARGES to let loose a mighty blow of pure force in a 30 foot line. Each creature in that area must make a Strength saving throw DC = 8 + proficiency bonus + Con.

On a failed save, a creature takes 1d8 force damage per charge expended, is pushed 10 feet away from you, and is knocked prone.

On a successful save, a creature takes half damage and no other effects occur.

Level 14: Catastrophic Impact

As an action while raging, you can leap into the air and come crashing down in an space within 20 feet of you. Every creature within a 10 foot radius of the point you land must make a Dexterity saving throw DC = 8 + proficiency bonus + Str.

On a failed save, a creature takes 4d10 bludgeoning damage and is prone and restrained beneath you. While a creature is restrained this way, it takes bludgeoning damage equal to 1d10+STR at the start of each of its turns. The creature can use it' action to make a Strength (Athletics) check against your DC, ending the effect on a success. You can only pin a number of creatures equal to half of your Constitution modifier rounded up. You end this effect early if you move from where you landed.

On a successful save, a creature takes half damage and is pushed to the nearest unoccupied space outside the radius.

The ability can be used a number of times equal to your proficiency bonus.