Pain Monger

A pain monger is the most primal and ferocious out of all barbarians, which takes a toll on their body. They channel this energy into pain for others to take. At higher levels they can reflect spells, and even drain the life from other creatures.

Spread the Wound.

 When you rage, you can use your action to cut yourself. You take slashing damage equal to your level, and this damage cannot be resisted in any way. Each creature of your choice within 10 ft. of you takes half of that damage (rounded up).

Magical Rebuke

 At 6th level, you can deflect magic casted on you and channel that energy back at the caster. When you succeed on a saving throw against a spell or other magical effect, you can cause the spellcaster to take force damage equal to the level of the spell.

Fearless Charger

 By 10th level, your acclimation with pain makes you more hardened and fearless. You have advantage on saving throws against being frightened, and once per turn, provided that you move more than 10 ft. on that turn, you can deal an extra 5 points of damage to one creature that you hit with a melee weapon attack. You must be raging to gain this benefit.

Destructive Link

Beginning at 14th level, you can cause a link of negative energy to connect yourself to a creature in the area of your spread the wound. As a bonus action on your turn, you can choose one creature that you can see within 10 ft. of you. That creature must make a Wisdom saving throw (DC 8 + your proficiency bonus + your Constitution modifier) or the effect takes place. While this effect is in operation, whenever you deal damage to creatures using  spread the wound, that creature takes slashing damage equal to the combined total damage dealt to all creatures within the area (not including you). This link lasts for one minute or until you stop raging. Once you setup a link with a creature, you can't do so again until you complete a short or long rest.