Path of the deathless

Deathless have little to no regard as to wether they live or die, they are bound by a never ending duty. As such, they continuously draw their power from their own self destruction and siphoning their life energy into their actions to gain a devastating edge. Their constant exposure to death has allowed them to grow adept in necromancy spells and only necromancy spells.

Divine retribution

At level 3, when you receive damage, you may imbue divine power into your weapon, using a reaction to imbue half the damage of the attack into yours as long as it doesn't exceed half of your total hit points. 

you may choose the damage type between radiant and necrotic

Necrotic

deal 1d6 + half your barbarian level as extra damage

Radiant

deal 1d6 + half your barbarian level as extra damage

Bestial rage

At level 3, Your rage knows no bounds, as such, in your enraged state your hair becomes a dull grey as a crimson miasma wafts around you as your body enlarges.

Giant Stature. Your reach increases by 5 feet, and if you are smaller than Large, you become Large, along with anything you are wearing. If there isn’t enough room for you to increase your size, your size doesn’t change.

Deathly adept

At level 6, you may cast an amount of necromancy spells equal to your proficiency bonus, for every spell slot you have to add a d10 to your 'sacrifice' for hp, this will take a bonus action and will not remove rage.

charges will reset every long rest.

Festering wounds

At level 10, you impart a fragment of the deathless inside you into your strike, causing the wounds you create to have a lingering effect.

when you strike an enemy, use your bonus action to remove (PB)d12 + constitution modifier from an enemies max health

Till death do us part

At level 14, when you reach below 50% health your armour class increases by 2 and can roll a (PB)d10 as a reaction to reduce incoming damage