Path of the Symbiont

The symbionts are strange, mimic-like entities with unknown
origins. Alone they are merely specks, barely noticeable for
most creatures. However, when they find a worthy host, the
symbionts unleash their true and terrifying potential.
Barbarians of the Path of the Symbiont draw their power
from those alien creatures. When entering a rage, the
Symbiont takes over and turns the barbarian into a violent
bloodthirsty monster, wielding the symbiont as a tangible
weapon with deadly precision. The symbiont hungers, and its
primal fury affects it's host. A symbiont may not always be
evil, but with a need to feed and an appetite for conflict, a
benign host, much less symbiont, is rare to find.

Symbiotic Blade

Beginning at 3 level, you bonded with a Symbiont, an alien
creature that takes the shape of various weapons. When you
enter a rage, the symbiont empowers you granting you the
following benefits:

You manifest your symbiotic weapon. You decide on the
weapons appearance. The weapon has the versatile
property and deals 1d10 + your Strength modifier, or
1d12 + your Strength modifier if wielded with two hands,
force damage.

Your symbiotic weapon cannot be disarmed.

You gain a +1 bonus to your AC.
The benefits last for the duration of your rage.
Additionally, when your features from this subclass subject
a creature to saving throw, the DC is equal to 8 + your
Proficiency bonus + your Strength modifier.

Apex Predator

Starting at 3rd level, the symbiont begins to further alter your
body. You gain Darkvision with a range of 120 feet and a
Climbing Speed equal to your Walking speed. While raging,
you ignore the drawbacks imposed by difficult terrain.

Eldritch Connection

Beginning at 6th level, your Symbiont develops the
Thrown(20/60) property.
     

       You can use a bonus action to call the weapon back to an
unoccupied hand while it is within 60 feet of you. If you do so,
the weapon spins back through the air towards you. Each
creature in a straight line between yourself and the symbiotic
weapon, must succeed on a Dexterity saving throw or take
2d6 force damage, or half as much on a successful one.

      Additionally, attacks with your symbiotic weapon ignore
resistance to necrotic damage when dealing necrotic damage
to a creature.

Apex Predator

At 10th level, the bond with the symbiont slumbering inside
you grows even stronger, making you a master at pursuing
and slaying your prey. You can manifest your symbiotic
weapon as a bonus action while you aren't raging.

        Additionally, whenever you finish a long rest, you can allow
your Symbiont to assimilate a magic weapon in your
possession. You can only assimilate a melee weapon you are
proficient with. Your symbiotic weapon gains any bonus to
attack and damage rolls and any properties of the assimilated
weapon, but maintains it's damage die. If the weapon
required attunement for any of its abilities, you can use them
as if you were attuned to it. You can only have one weapon
assimilated at a time. You can replace the assimilated
weapon with another whenever you finish a long rest.

Symbiotic Rage

At 14th level, you can release the beast inside you and let the
symbiont take over. When you are raging, you can use a
bonus action to enter a symbiotic rage. While you are in this
form, you gain the following benefits:

You gain blindsight in a range of 15 ft.

You regenerate 1 hit point at the start of each of your
turns.

Your symbiotic weapon gains a reach of 10 ft.

The bonus to AC from your symbiotic weapon increases to
+2.

You gain resistance to necrotic, poison, and psychic
damage.

If your turn ends and you haven't hit and damaged a creature
since your last turn, your symbiotic rage ends or you can take
1d12 necrotic damage to prolong the duration for one
additional round. The damage you take from this ability can't
be reduced by any means.