Path of the Inner Demon

You are a primal warrior with a dark creature living behind your rage.

Inner Demon

Starting when you choose this path at 3rd level, when you rage your body goes through many changes. You gain these benefits while raging if you aren’t wearing heavy armor:

Your size doubles in all dimensions, and your weight is multiplied by eight. This growth increases your size by one category-- from Medium to Large, for example. If there isn't enough room for you to double in size, you attain the maximum possible size in the space available. You lose profiency in all weapons except your fist. Also you can roll a d12 in place of the normal damage of your unarmed strikes.

Demon's Rage: At the start of your turn, if you’ve taken any damage since the beginning of your last turn, you must make a Intelligence saving throw to maintain control. The DC equals 10, or half of the total damage you’ve taken from attacks since your last turn, whichever number is higher. On a failed save, you must move directly towards the nearest creature to you and use the Attack action against that creature. If there is more than one possible target, the DM chooses the target. You then regain control for the remainder of your turn.

Juggernaut

Beginning at 6th level, While you are raging you have advantage on all saving throws that try to impose a condition on you blind, poisoned, charmed, etc. Also while raging any save to end an effect on you happens at the start of your turn.

Relentless Demon

Beginning at 10th level, At the start of each of your turns while raging, you regain hit points equal to 1 + your Constitution modifier. Also now whenever you land a critical hit you double your rage bonus damage for that attack.

Demon Symbiosis

Starting at 14th level, You have finally learned to control your in demon. You have advantage on your roll for Demon's Rage. Also you gain resistance to all damage.

Demon's Rage: At the start of your turn, if you’ve taken any damage since the beginning of your last turn, you must make a Intelligence saving throw to maintain control. The DC equals 10, or half of the total damage you’ve taken from attacks since your last turn, whichever number is higher. On a failed save, you must move directly towards the nearest creature to you and use the Attack action against that creature. If there is more than one possible target, the DM chooses the target. You then regain control for the remainder of your turn.