Path of the Sibyl

Certain cultures revere those who are touched by madness and record their gibbering as portents from the gods.

Visons of Madness

Your madness allows you to get glimpses of the future.  At 3rd level when you adopt this path, you gain the ability to cast Augury as a ritual.

Mad Rage

Starting when you choose this path at 3rd level, you can tap into your madness when you rage, giving you an intuitive foresight that allows you to predict incoming attacks. If you do so attacks against you have Disadvantage for the duration of your mad rage. You also have Disadvantage on all Wisdom checks and saving throws for the duration of your mad rage as your vision and other senses are assaulted with sensory input from the future.

Fortune Favors the Mad

Starting at 6th level, you have the ability to twist fate using your intuitive connection to your oracular madness. When you or a creature you can see makes an attack roll, an ability check, or a saving throw, you can use your reaction to roll 1d4 and apply the number rolled as a bonus or penalty (your choice) to the creature’s roll. You can do so after the roll but before any effects of the roll occur. Once you have used this ability the number of times shown for your barbarian level in the Rages column of the Barbarian table, you must finish a long rest before you can do so again.

Infectious Madness

Beginning at 10th level, your madness becomes infectious, reaching out to twist the minds of those who get too close. The first time a creature comes within 10 feet of you during each of your mad rages, they are subject to the Confusion spell. The DC is equal to 8 + your proficiency modifier + your Constitution modifier.

Mouthpiece of the Gods

Starting at 14th level, you gain the ability to cast Contact Other Plane as a ritual. You make the Intelligence saving throw with proficiency. Succeed or fail, when you try to communicate the knowledge gained from this spell you either speak only in cryptic poetry or in complete gibberish. Anyone listening must make a DC 15 Religion check to get a general idea of what you're trying to communicate.