Comments from the Finger: This is a weird gem converteout of 3.5, but I think it'll fit into our desert-themed material nicely.
Path of the Scorpion
The scorpion is thought to represent revenge and death, but to those who live in the vast desert wastes, the scorpion has come to symbolize stealth, passion, and preservation in the face of extinction. After all, the scorpion cannot be killed by the untamable waste, and it bows to no power other than its own. Some barbarians of the wastes worship at altars dedicated to ancient scorpion gods, and become Scorpion Heritors, men transformed by the Waste into forms better adapted to their harsh environment. With time, they come to possess the power of scorpions, and even begin to resemble them.
Starting when you adopt this path at 3rd level, you know how to strike subtly like a scorpion. Once per turn, while you are raging, you can deal an extra 1d6 damage to one creature you hit with an attack if you have advantage on the attack roll. The attack must use a finesse or a ranged weapon.
You don’t need advantage on the attack roll if another enemy of the target is within 5 feet of it, that enemy isn’t incapacitated, and you don’t have disadvantage on the attack roll.
This extra damage increases as you gain levels in this class. At 6th level, it increases to 2d6, at 10th, it increases to 3d6, and at 14th it increases to 4d6.
Starting at 6th level, you gain proficiency in Stealth and Survival and you can add twice your proficiency bonus to Dexterty (Stealth) and Wisdom (Survival) checks you make while you are in the desert.
At 10th level, you have immunity to poison damage and can't be poisoned. Additionally, while you are raging, you can deal your additional damage from Sneak Attack as poison damage.
Starting at 14th level, while you are raging, you sprout a spectral, yet tangible, scorpion tail. This tail is a finesse, reach weapon which cannot be disarmed and deals 1d8 poison or piercing damage (your choice) on a hit. When you take the Attack action on your turn, you can make an additional attack using your tail.
Changelog: 5/16/16: Description: Typo fixed
Scorption Tail: Changed to allow you an extra attack with the tail. Critical hit stuff removed. Damage reduced.
5/18/16: Scorpion Instincts: You now get proficiency while not in deserts, and twice proficiency while in them.