Path of the Seismic Warrior

Legends speak of warriors whose strength rivalled the whole world, many had witnessed their power shattering landscapes, crumbling mountains and even pushing whole continents beyond the horizon, it was said the ground itself feared them and would shudder and writhe as they marched into battle.

The Seismic Warrior harnesses the unpredictable nature of the world's core and channeling it into bursts of unrelenting power. Indeed, to face a Seismic Warrior in combat is the know the wraith of the an earthquake and volcano combined. 

Seismic Stomp

Starting at 3rd level you can shake the very ground beneath your feet while raging. On each of your turns as a bonus action, you can create a almighty shockwave in a 15-ft cone. all grounded creatures within this cone must make a strength or dexterity saving throw (you choose and the choice applies to all creatures). On a failed save the creature is knocked prone, all creatures larger than medium has advantage on this saving throw.

The Saving throw equals 8 plus your proficiency bonus and your strength modifier.

One with the World

At 6th level your attunement with the World and its mantle has granted you new abilities. You have gained a resistance to fire damage and when raging the ground inside a 10 ft radius of you becomes difficult terrain to all enemies.

Natural Pillar

At 10th level you can harness the earth around you to protect yourself and your friends.

When a creature attacks you or an ally within range (30ft) you can use your reaction to erect a 5ftx5ft barrier between the attacker and the recipient to order to block the attack. The pillar pushes all creatures out if its space and takes on the properties of the environment surrounding it, it can be made from earth, stone, sand or ice depending on the GM's discretion. The pillar has the same AC as you and it's HP equals 2 times your barbarian level. The pillar lasts for the duration (10 minutes) and can only be prematurely dismissed either with a bonus action, if you create another pillar as a separate reaction or if an attacker reduces the wall's HP to 0.

Additionally, you can use the pillar as a weapon, if the pillar is within range of your Seismic Stomp it bursts apart with violent force. Not including yourself all creatures within a 5ft radius of the pillar must make a Dexterity saving throw or take 1 D8 piercing damage or half as much on a success.

The Saving throw equals 8 plus your proficiency bonus and your strength modifier.

Improved Seismic Stomp (Seismic Plume)

At 14th level you've channel into the full power of the World's core and can release it in a devastating blast. Whenever you use Seismic Stomp you also release a plume of debris, this plume launches 30ft upwards and disperses out in the 15ft cone away from you, the plume takes on the properties of the environment around it depending on the GM's discretion. All creatures inside this plume airborne or otherwise must make a strength or dexterity throw (You choose, the choice applies to all creatures) on a failed save grounded creatures are knocked prone and airborne creatures are forced to the ground, all creatures larger than medium has advantage on this saving throw.

The Saving throw equals 8 plus your proficiency bonus and your strength modifier.