Path of the Eldritch

A barbarian's strength of emotions manifests in physical might. A barbarian that follows the Path of the Eldritch has that might empowered by supernatural forces. Whether forced upon the barbarian, or chosen by entering into a lesser version of a pact with a mysterious being similar to how many Warlocks gain their power, a Path of the Eldritch barbarian acquires strange and otherworldly abilities that augment the barbarian's natural abilities.

Level 3: Eldritch Infusion

At 3rd level, your otherworldly patron infuses you with supernatural energy, bolstering your abilities, influenced by the nature of your voluntary or forced pact:

• Pact of the Weapon
• Pact of the Spellbound
• Pact of the Insightful
• Pact of the Emblem

Whenever you gain the Ability Score Improvement feature, you can exchange your selected Pact for another one, or you can exchange the Pact of the Emblem's Eldritch Invocation for another Invocation for which you meet the prerequisites. Any feature dependent on these changes would be changed as this time, too. For instance, if this change makes you ineligible for any of your other Eldritch Invocations, you must also replace them now, choosing invocations for which you now qualify.

Pact of the Emblem

One or more Eldritch rune forms on your body, granting you one Eldritch Invocation of your choosing. The prerequisites for the chosen invocation must be met, except for Pact feature requirements. When an invocation uses a Pact's object, such as requiring the Pact of the Tome's Book of Shadows, you can manifest their features on your skin, such as gaining a tattoo of someone's name to fulfill the Gift of the Protectors invocation, and you are your talisman for Pact of the Talisman invocations.

/** I don't have an option to add Invocations to custom subclass or adding the Eldritch Adept feat as a workaround. So this option is basically "broken". Write it in Notes. */

Pact of the Insightful

Your perception and insight heightens when you are in a particularly vulnerable situation, allowing you some small ability to predict your opponent's movements. When an attack roll made against you is rolled with advantage and hits you, your infused pact magic allows you to use your Reaction to force a reroll. Roll a single d20, and the attack uses the new rolled result, but cannot result in a critical hit even if the dice roll is within the critical threat range for the attacker. Whenever this ability causes an attacker to miss you, you gain a bonus to your AC until the start of your next turn equal to your proficiency bonus.

Even if you have multiple Reactions, you can only use this ability once until the start of your next turn.

Pact of the Spellbound

You can tap into the magic infused into your body to wield limited magic. When you gain this feature, choose any two melee attack cantrips. You can cast those cantrips at will. Constitution is your spellcasting ability for these cantrips.

Pact of the Weapon

Your supernaturally charged body infuses into your weapons. In a battle where you have already used your rage or are currently raging, you gain the benefits of this feature for any weapon you are proficient with and are wielding, including your unarmed strike. The weapon is treated as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage for all attacks you make with that weapon. The weapon you wield takes on a sinister form, dealing an additional psychic damage equal a number of d4 dice equal to your proficiency bonus.

Level 6: Otherworldly Tenacity

When you are under an external influence that impedes your volition to move or act of your own accord from a magical effect (such as those listed below), or even being Frightened, and enter a Rage, you automatically and immediately make another save against the effect, even if you are not normally afforded one, as the supernatural empowerment from your eldritch source has granted you automatically attempts to protect you from such effects. While your Rage is active, you can reroll any save against being Frightened or any of the below conditions from a magical source, as if using a luck reroll:
Charmed, Frightened, Incapacitated Paralyzed, Petrified, Restrained, Stunned, and Unconscious.

A successful save ends Charmed, Frightened, and Unconscious conditions, and suppresses the other conditions until the end of your Rage.

Level 10: Cosmic Rampage

As your anger surges, an extradimensional portal opens as material symbolic of your source of power (such as Lovecraftian tendrils from the Great Old One, Great Cthulhu) wraps around your body, pulling you through the portal, and shunting you to a nearby location, only to disappear back into the portal. When you enter a Rage, you can teleport up to half of your movement speed. You can use this feature before or after you use Instinctive Pounce.

Additionally, you gain the following benefits based on your chosen Pact while you are raging:

• Pact of the Weapon: Polyweapon
• Pact of the Spellbound: Spellwrath
• Pact of the Insightful: Manipulative Intuition
• Pact of the Emblem: Runic Tempest

Manipulative Intuition

The understanding of your foes form the otherworldly magic that permeates your body allows you subtly influence a target's body.

As a Bonus Action while you are raging, you can make a single weapon attack. If this attack hits your target, the damage you deal does not include your ability score modifier, but you bestow a curse open the target that lasts until the start of your next turn.  Constitution is the ability score for the saving throw DC. The following are the optional effects of your curse:

• The target's speed is reduced to 0, if they fail a Wisdom saving throw.
• If the target uses magic to relocate, they take force damage based on your proficiency bonus, then they make a Concentration save or lose the spell. The damage equals a number of d4 equal to your proficiency bonus, plus your proficiency bonus.
• The target cannot take reactions towards or against anyone other than you.
• The target must make a Constitution saving throw when they hit anyone other than you. On a failed save, you draw out their life force to heal you for a number of hit points equal to your proficiency bonus.
• The target must make a Charisma saving throw. On a failure, the target is vulnerable to the damage from the next attack roll that hits the target.

Polyweapon

Your Pact of the Weapon allows you to supernaturally morph your weapon to any other weapon with which you have proficiency, including to or from your Unarmed Strike, of your choosing. The weapon is an even more grotesque version of itself, but allows you to take advantage of multiple Weapon Masteries in a single turn. You can only change the weapon once per turn, but can do so in between weapon strikes. Any magical properties of the weapon are transferred to the new form, and the weapon reverts to its original form when your Rage ends.

Runic Tempest

Your magic rune(s) leaves your body and either splits or multiplies into tiny, wispy light versions of your eldritch rune. These runes encircle your body to protect you at a distance of 15 feet for the duration of your Rage, or for 10 minute, whichever is sooner. Should this feature end before your rage, you can use an action to reactivate this feature. You can designate any number of creatures you can see (or that are an ally that you know is near you) to be unaffected by the runes. Similar to the Spirit Guardian spell, an affected creature's speed is halved in the area, but when the creature enters the area for the first time on a turn or starts its turn there, the creature takes 1d10 force damage. Additionally, the creature has disadvantage on ability checks while within the runes' field of effect.

Spellwrath

The magic infused into your body saturates it even further. You can now use your cantrips granted by this Pact and gain the following improvements while your Rage is active: the range of effect is increased to 15 feet (for example, Booming Blade could attack a target 15 feet away rather than 5 feet) even though it remains a melee spell attack, the casting time is reducible to a bonus action, and do not require concentration (one spell at a time only).

Level 14: Banishing Toll

As an Action, you can harness your rage to force your strangely sourced power to shunt the target of your weapon attack to an otherworldly plane, possibly as an offering to your patron that even you were unaware you were making. As your weapon vibrates with force energy, the attack deals extra force damage equal to a number of d10 equal to your levels in this class divided by 4.

If this attack reduces the target to 50 hit points or fewer, the target is banished (per Banishing Smite). If the target is native to a different plane of existence than the one you’re on, the target is banished with a faint popping noise, returning to its home plane, you believe. If the target is native to the plane of existence you’re on, you banish the target to a harmless demiplane. While there, the target is incapacitated. The target remains there until the spell ends, at which point the target reappears in the space it left or in the nearest unoccupied space if that space is occupied.

If the target is not reduced to 50 or fewer hit points, they must make a Charisma saving throw against your Constitution-based spell DC or be banished (per Banishment). If the target is native to the plane of existence you’re on, you banish the target to a harmless demiplane. While there, the target is incapacitated. The target remains there until the spell ends, at which point the target reappears in the space it left or in the nearest unoccupied space if that space is occupied. If the target is native to a different plane of existence than the one you’re on, the target is banished with a faint popping noise, presumably returning to its home plane. If the spell ends before 1 minute has passed, the target reappears in the space it left or in the nearest unoccupied space if that space is occupied. Remember, you cannot cast or maintain concentration on spells while raging (as part of starting this Action, you can choose to drop your Rage). Otherwise, the target doesn’t return.

Once you use this feature, you can’t use it again until you finish a Long Rest unless you expend a use of your Rage (no action required) to restore your use of it.

The above does not preclude the possibility that your supernatural patron is actually redirecting these banished creatures.