Path of the Eldritch Shards

In short, crystals grow inside of you that give you extra powers.

Eldritch Emanation

3rd-level Path of the Eldritch Shards feature

The crystals inside of you resonate with your rage, releasing an aura of harmful energy. While you’re raging, creatures that begin their turn within 15 ft. of you take psychic damage equal to 1d4 + half your barbarian level and have their speed reduced by 10 ft.

Armored Crystallization

3rd-level Path of the Eldritch Shards feature

The crystals within you burst from the inside out, covering parts of your body even further and providing extra protection against your opponents. While raging, your Unarmored Defense becomes 12+CON+WIS instead of the usual value.

Mental Rebuke

6th-level Path of the Eldritch Shards feature

The influence of the crystal grows even further, providing protection against the harmful effects of mental manipulation. Thanks to their influence, you get advantage on Wisdom Saving Throws.

When you successfully resist a check using this feature, you can use your reaction to attempt to turn the effect that caused the check back on that creature. The creature must succeed on a Wisdom saving throw against a DC that equals 8 + your proficiency bonus + your Constitution modifier or suffer the effects of its own power. If the effect needs concentration, you can concentrate on its effects even while under the effects of rage.

You can use this reaction once per long rest.

Shard Barrier

10th-level Path of the Eldritch Shards feature

With time, you learn how to better control the shards within you, allowing the creation of a barrier to ward off attacks and deliver them back to your enemies. 

As a bonus action, you can form an energy barrier around you, giving you temporary hit points equal to 1d10+your barbarian level. When the barrier is depleted, all creatures within 5 ft. of you must make a Dexterity saving throw or take 1d10 force damage. The damage is halved on a successful save.

The temporary hit points and force damage die increase to 3d10 at level 17.

You can use this feature a number of times equal to 1 + your Constitution modifier (minimum of 1), and you regain all expended uses when you finish a long rest.

Horrific Burst

14th-level Path of the Eldritch Shards feature

The shards inside of you have fully attuned to your body, allowing you to release their presence to terrify your foes.

Once per long rest, when you enter your rage, every enemy within 60 ft. of you must make a Wisdom saving throw. On a failure, the enemy take 5d12 psychic damage and becomes frightened for 1 minute. As long as they remain in that condition, their movement speed is reduced to 0. On a successful save, they take half the damage and the fear effect only lasts until the end of their next turn.

Enemies affected by Horrific Burst can repeat the saving throw to resist its effects at the end of their turns. The DC equals 8 + your proficiency bonus + your Constitution modifier.