Path of the Demon Marked

Those who follow the Path of the Demon Marked or commonly called the marked are often individuals selected to enter the service of an archfiend from a young age. Groomed to be servants and instruments of their will, the marked are forced to serve and carry out great evil. These individuals are worth a great deal to slavers and mercenaries as anyone with gifts from an archfiend could likely succeed them if they live long enough to acquire their fully realized power. Immense destructive power and secret magic counters are the most prominent of these gifts.

Demon Mark

Beginning at level 3 when you are raging an apparent mark of fiendish power appears on your face. You gain resistance to necrotic damage while raging if you do not already have it. You also gain proficiency in intimidation, deception or acrobatics.

Hellblaze

Starting at level 3 while your demon mark is active you have access to a pool of d6s the number of which is equal to half your barbarian level. When you hit with a weapon attack you can choose to expend them as extra damage. The number of which you can use at once is equal to your constitution modifier. This damage is either fire or necrotic. You recover all spent d6s on a long rest.

Counter Magic

At 6th level you can call upon ancient forbidden magic that allows you to deflect magical attacks. When you choose to hold your turn you can use your reaction to deflect a spell attack or AOE spell targeting you or an adjacent ally within 5 feet back at the caster. You must be holding a finesse weapon and not be incapictated. If you are raging, doing so ends your rage. 

You can use this ability a number of times equal to your proficiency modifier. You regain all uses after a long rest.

Greater Demon Mark

At 10th level, your attacks now ignore slashing, piercing, bludgeoning, fire and necrotic resistance. 

You can also spend a hit die to recover d6s from your demon mark pool. One hit die per d6.

Revenge Counter

At 14th level, as an action you can feign being overwhelmed in combat. For one round you are vulnerable to all damage and all attacks against you have advantage. The total damage you take can be stored for a number of rounds equal to your constitution modifier. On your turn as an action, as long as you are not restrained, grappled or paralyzed, you can unleash a cone of vengeful energy dealing the same amount of damage you took to all creatures in a 60foot cone. The damage is force damage. You gain one level of exhaustion after usage. If the damage is not expended you drop to 0 hitpoints.

You can use this ability again after a long rest.