Path of the Hellrager

Barbarians who follow the Path of the Hellrager draw their rage from the flames of Hell itself. These barbarians channel their rage into explosive attacks, always going for the weak spot, never letting anyone get a hit on them without giving one right back, as unforgiving as Hell itself.

Guide Them to Hell

Starting when you follow this path at 3rd level, you use the fear your attacks inflict on others to drive your weapon even deeper. Once per turn, when you score a critical hit or reduce a hostile creature to 0 hit points while raging, you may make an additional melee weapon attack as part of the Attack action on your turn. In addition whenever a hostile creature scores a critical hit against you while raging, you may immediately make a free action attack against them.

Fire and Brimstone

Your connection to Hell grants you a sense for those who belong there, and an affinity to fire. You can cast the cantrip control flames at will, and as an action, you can open your awareness to detect those from the Lower Planes. Until the end of your next turn, you know the location of any fiend within 60 feet of you that is not behind total cover. You can use this ability a number equal to your proficiency bonus per long rest.

Spark of Hellfire

Beginning at level 6, the hellfire simmering inside you explodes out when you wield your weapon, guiding you towards your enemy’s death, and even leaping towards enemies itself, trying to consume them in your rage. Your weapon attacks now score a critical hit on a roll of 19 or 20.

Whenever you hit a creature with a weapon attack while raging, you can force it to make a Wisdom saving throw(DC 8 + your Con mod + prof bonus). On a failure, you can choose to inflict it with one of the following effects.

Madness

On the creature's next turn, it must use its action to make a weapon attack against the nearest creature. If this attack is against anyone other than you, it takes 2d10 fire damage, or 4d10 if they deal a critical hit.

Fury

The creature takes 2d10+your barbarian level in fire damage and the next weapon attack the creature makes against you is a critical hit.

You can use this feature a number of times equal to your proficiency bonus per short rest. 

Hell's Blessing

When you reach 10th level, your rage is so fear-inducingly terrifying that even Hell itself doesn't want your soul, so you've been blessed with a gift to keep you out of Hell as long as possible. You gain resistance to fire, and while raging, critical hits cannot reduce you below 1 hit point.

Infernal Bloodlust

At 14th level, your bloodlust cannot be quenched nor fulfilled. When you deal a critical hit, you can choose to double the number of brutal critical dice, or you can target a second creature that you can see within 30 feet of you. They take 4d10 + your barbarian level in fire damage if they fail a Dexterity saving throw, half damage on success. You can use this feature a number of times per long rest equal to your proficiency bonus.