Infernal Half-Homunculus

You were plucked off the street and experimented on so thoroughly that you lost all sense of self. Now having half of your organs being replaced by that of a demon's, you wander the world with a purpose that you know nothing of. The only thing you know is that once that purpose is fulfilled, you will die.

Thanks to your demonic half, you have gained unimaginable strength and durability. But at what cost? You are no longer human. You have to suppress your humanity, or else risk death. Only the blood of a dragon can keep you stable in that state, and dragons are not very common nowadays.

Unarmored Defense

Starting at 3rd level, when not wearing armor or wielding a shield, your AC equals 10 + CON mod + STR mod.

Emotionless Demeanor

You gain proficiency in Intimidation if you don’t have it already. If you do, you gain expertise in Intimidation. Additionally, you can add your strength modifier to any Intimidation check you make.

Physical Boost

At 3rd level, you gain the ability to tap into your demonic half. As a bonus action, you can add an extra d4 damage to any attack you make. This value increases as you level up, with it becoming a d6 at 7th level, a d8 at 10th level, a d10 at 15th level, and 2d10 at 18th level. Additionally, your AC is raised by a value equal to your proficiency bonus. The effect lasts for 1 minute and can only be used once per long rest.

Uncanny Durability

At 7th level, once per long rest, if you fail either a Constitution or Strength saving throw, you may reroll the save, and choose between the two numbers.

You also add a permanent +2 bonus to either your Strength or Constitution score.

Frightening Aura

When you use Physical Boost, you now gain the ability to emit a frightful aura. Any creature who can see you who is not one of your allies must succeed on a contested Wisdom vs. Strength (Intimidation) check or be frightened for the duration of your ability.

Inanimate Nature

Due to your magical nature (being a magical item yourself), you may choose to use an action to attune or un-attune with any magic item you have in your possession. Additionally, if you cannot do so already, you no longer have to eat, sleep, or breathe.

True Demon Form

At 15th level, whenever you use your ability, you now have a flying speed equal to half your walking speed. This flying speed also allows you to levitate for the duration of your ability. However, if your ability runs out while you’re in the air, you fall and take the appropriate amount of fall damage (1d6 for every 10 ft. fallen.)

Ultimate Durability

When you use Physical Boost, you gain resistance to all incoming sources of damage both magical and nonmagical. This effect ends when Physical Boost ends.