Path of Undeath

You can say it is lucky or unlucky, but there is definitely luck in involved for this path to be followed. This path follows the strengths of undeath without succumbing to the submission of a Lich or Death tyrant, showing Orcus' blessing or curse to be difficult to follow. 

Insatiable Hunger

Starting when you choose this path at 3rd level, you can strengthen your endurance by feasting on creatures you slay. You can use half of your movement to feast on a creature you have slain and gain temporary hit points equal to your Constitution modifier + half your Barbarian level rounded down. If you feast while you are raging, you gain temporary hit points equal to double your Constitution modifier + your barbarian level. After 1 hour, any remaining temporary hit points gained this way are lost. Once you have feasted, you cannot do so again until you finish a short or long rest.
     You cannot feast on anything not made of human flesh. For example, you cannot feast on anything incorporeal like a ghost, you cannot feast on the stone or iron of a golem, and you cant feast on bloodless vegetation that lacks the proteins of flesh. You can, however, feast on the rotten flesh of a zombie, eat around the stitches of a flesh golem, or eat any dead creatures captured in the vines of a shambling mound.

Rampage

Beginning at 6th level, you can use the rush of killing to continue your rampage. Whenever you are raging and you drop a creature to 0 hit points, you can then use a bonus action to move up to half your speed and make one melee attack.

Impatient Hunger

Beginning at 10th level, your taste for flesh has made you impatient for your next feast. You can now use your insatiable hunger on a living creature. In order to feast on a living creature if it is unwilling, the creature must make a strength saving throw against a DC equal to 8 + your proficiency bonus + your constitution modifier.

Orcus' rage

Starting at 14th level, you can choose to imbue your rage with some of Orcus' power. While you are raging and you drop a creature to 0 hit points, that creature rises the next turn as a zombie under your control. The zombie has the statistics of the creature that was slain, but gains the undead fortitude ability and cannot cast spells. The zombie can understand your requests, even in your incomprehensible rage but cannot speak.
     You can only have five zombies under your control. If you raise another zombie, the oldest zombie you raised is destroyed. Once you stop raging, all zombies under your control are destroyed and you gain a number of levels of exhaustion equal to half the total number of zombies you raise rounded up (maximum of 3). Levels of exhaustion gained this way can be lost from one long rest rather than three separate long rests.