Path of Erathaol

You fight in the name of Erathaol, the Seer.  Erathaol rules Venya, the Pearly Heaven and the third of Celestia’s layers. A patron of prophets and seers, Erathaol forecasts planar events before they unfold and watches over children destined for greatness. He also oversees a vast library that includes thousands of historical codices, written laws, and celestial canticles. 

Erathaol watches the universe unfold from Xiranthador, an undersea library-fortress made of colossal seashells set with ornate mother-of-pearl mosaics. The fortress holds more books and scrolls than can be read in one thousand lifetimes.

Your "rage" is not a surge of anger, but a heightened awareness as knowledge suddenly floods your mind.

Overwhelming Knowledge

At 3rd level, your weapon strikes impart some of the vast lore of Erathaol's library, overwhelming your enemies' minds. While you're raging, the first creature you hit on each of your turns with a weapon attack takes extra psychic damage equal to 1d6 + half your Barbarian level.

Heaven's Heart

Beginning at 6th level, you can't be charmed or frightened while raging. If you are charmed or frightened when you enter your rage, the effect is suspended for the duration of the rage.

Librarian's Blessing

At 10th level, Erathaol lends you some of his great knowledge and prophetical ability.  You gain proficiency in either Arcana, History, Nature, or Religion.

You can cast Divination without any material components.  You can even cast it while raging, and your rage continues if you cast it.  Once you use this feature, you can’t use it again until you finish a long rest.

Portent

Starting at 14th level, glimpses of the future begin to press in on your awareness.  When you finish a long rest, roll two d20s and record the numbers rolled.  You can replace any attack roll, saving throw, or ability check made by you or a creature that you can see with one of these foretelling rolls.  You must choose to do so before the roll, and you can replace a roll in this way only once per turn.

Each foretelling roll can be used only once.  When you finish a long rest, you lose any unused foretelling rolls.

You are encouraged to replace the 20th level feature Primal Champion with the following ability:

Seer’s Sight

By 20th level, Erathaol has taught you how to see into the immediate future.  You can spend an action to briefly gain incredible foresight.  For 1 minute, you can’t be surprised and have advantage on attack rolls, ability checks, and saving throws.  Additionally, other creatures have disadvantage on attack rolls against you for the duration.