Primal Path
At 3rd level, a barbarian gains the Primal Path feature, which offers you the choice of a subclass. The following option is available to you when making that choice: Path of the Fallen.
Path of the Fallen
Barbarians whom follow the Path of the Fallen stem from secluded tribes found throughout the world. These tribes revere the dead, bathing themselves in their ashes and marking themselves for war with paste made from bones. When a great warrior of the clan dies, their remains are often gifted to a fellow combatant or next of kin so that they may perform the bone rite, a ritual which allows the deceased to continue fighting for their tribe alongside the ritualist.
Amongst the Dead
When you choose this path at 3rd level, you are able tread amongst the dead by producing a necrotic aura which fools their senses. When you activate this feature using your action, you are undetectable by undead until you lose concentration or take a hostile action, for up to a maximum of 1 hour. An undead becomes immune to this effect for 24 hours after you are noticed by it. True Sight can detect you as if you were not using this ability.
Once you use this feature, you can’t use it again until you complete a long rest.
Rouse the Dead
Also at 3rd level, your rage calls forth the restless remains of a warrior from a battle long passed. When you rage, you summon a skeletal warrior that uses the Skeleton stat block to an unoccupied space within 30 ft. (the DM has the skeleton's game statistics). Its hit point total is equal to 3 x your barbarian level, your Rage Damage is added to its Dexterity score, it adds your proficiency to its attack bonus, and its attacks fuel your rage allowing your rage to persist. It can carry and equip up to 150 pounds of gear and will always carry the objects given to it even after disappearing.
At the end of each of your turns while raging, you can mentally command the skeleton if it is within 60 feet of you. You decide what action the skeleton will take and where it will move during its next turn, or you can issue a general command, such as to guard a particular chamber or corridor. If you issue no commands, the skeleton only defends itself against hostile creatures. Once given an order, the skeleton continues to follow it until its task is complete.
The skeleton is under your control until your rage ends or until it is reduced to 0 hit points, after which it crumbles to the earth, only to disappear when you stop raging. You can also dismiss the skeleton at any time as an action, causing it to disappear. In either case, entering a rage again summons the same skeleton, restored to its hit point maximum.
Gray Tongue
At 6th level, you can cast the spell speak with dead as a ritual. Furthermore, you are capable of understanding, and can be understood, by any dead or undead which you communicate with, as long as all parties have at least one language and can hear the other.
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Rattling Bones
Also at 6th level, while raging, your can use your bonus action while your skeleton is within 5 feet of you to turn it into a storm of bones that surrounds your body for 1 minute. For the duration, the skeleton moves with you and can't be targeted or damaged. The skeleton can use its action and reactions to make attacks in this form.
Additionally, ranged attacks against you have disadvantage, and the first time creature enters the area within 5 feet of you on their turn, or that starts their turn within that area, they take 1d6 + your rage damage as bludgeoning damage.
At the end of this duration, the skeleton reassembles in an unoccupied space within 5 feet of you with its maximum hit points. Alternatively, you can use this feature while your skeleton is at 0 hit points to restore it to its maximum hit points.
Once you use this feature, you can't use it again until you finish a short or long rest.
Vengeful Dead
At 10th level, the hands of the long buried dead reach up from the earth to hinder your foes. As an action, you can summon forth skeletal hands that emerge from the ground beneath up to 4 creatures of your choice that you can see within 60 feet of you. The space the targets occupy when you use this feature becomes difficult terrain for 1 minute. A creature who starts their turn in this difficult terrain must make a Strength saving throw (DC 8 + your proficiency bonus + your Strength modifier) or be grappled by the hands.
Once you use this feature, you can't use it again until you finish a long rest.
Rage Beyond Death
At 14th level, your rage and desire to fight are both so great that they empower you to do so, even in the afterlife.
While raging, having 0 hit points does not knock you unconscious. You still must make make death saving throws, and you suffer the normal effects of taking damage while at 0 hit points. However, if you would die due to failing death saving throws, you don't die until your rage ends.
Credits
Created by Anthony Vallozzi, you can contact me on reddit as /u/ch33ri000z. You can find my work and follow me for updates at gmbinder.com.
Thanks to everyone in the Discord of Many Things who assisted with so much.
Art in Order of Appearance
"Necromancer" by Markus Neidel
"Undead sketch" by Giancarlo Ganzaba
Anthony Vallozzi - Patreon.com/AnnalsOfAdventure