Marrow Knight

Either through magical experimentation, divine gifts, or just a quirk of biology, you can shape your bones in ways that no other creature can. While it may look grotesque or painful to the unfamiliar, you feel no pain from your gifts. You're proud of the fact that you don't need to rely on iron or steel to protect yourself like other warriors do. You may even revel in the shocked reactions your fighting style produces.

Anatomical Knowledge

When you choose this archetype at 3rd level, you gain proficiency in Medicine and you have advantage on Medicine checks when treating skeletal injuries.

Bone Armements

You can create bone weapons by having them grow out of your body. This doesn't do damage to yourself. As an action you can create up to two bone armaments. These weapons can take the shape of any melee weapon that you are proficient with, and they use that weapon's statistics. Only you are proficient in their use, and they disintegrate into dust at the end of your turn if they are not in your hands. You can take an action to reincorporate you bone armaments back into yourself.

You can create a number of bone armaments equal to  3 + your proficiency bonus, and regain all uses of this ability once you finish a long rest. Reincorporating a bone armament also regains one use of this ability.

Bone Armor

At 3rd level, you chose one type of bone armor: Scale or Plate. Once chosen, it can't be changed. While not wearing armor you can use an action to create your set of bone armor. You can also create your bone armor in the same action you create bone armaments. This armor can't be removed. You can take an action to reincorporate you bone armor back into yourself and you can do this in the same action you reincorporate bone armements.

You can create bone armor a number of times equal to your proficiency bonus, and regain all uses of this ability once you finish a long rest.

Plate Armor

While you are wearing your scale bone armor, you have the following benefits:

• Your Armor Class is 17
• You gain resistance to Slashing and Piercing damage
• You have advantage on Strength check and Strength saving throws
• You have advantage on Charisma (Intimidation) checks

Scale Armor

While you are wearing your scale bone armor, you have the following benefits:

• Your Armor Class is 12 + Dex modifier
• You gain resistance to Slashing damage
• Your base speed increases by 5 feet
• You have advantage on Dexterity checks and Dexterity saving throws

Osteo-Empowerment

You can create you weapons and armor even faster, and they are even stronger than before. You can use Bone Armaments and Bone Armor as bonus actions, and your Bone Armaments count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage.

Bone Flechette

You can spray bone shards in a 60-foot cone that does 8d8 Piecing, Slashing, or Bludgeoning damage on a failed Dexterity save, or half as much damage on a successful one. The save DC equals 8 + your proficiency bonus + your Constitution modifier. At 14th and 18th levels the damage increases by 2d8. 

Once you use this feature, you can’t use it again until you finish a long rest.

Osteo-Perfection

You have perfected your bone armor and armaments. Your bone armor gains additional abilities as detailed below. It no longer takes an action to create or reincorporate bone armor or armaments. Any bone armament you create acts as a +1 magic weapon, although they still disintegrate at the end of your turn if they are no longer in your hand.

Improved Plate Armor

• Your Armor Class is 18
• You gain resistance to Bludgeoning, Piercing, and Slashing from Nonmagical Weapons
• You have advantage on Strength check and Strength saving throws
• You have advantage on Charisma (Intimidation) check
• You have advantage on Constitution saving throws
• Any creature you attack you with either natural weapons, and any creature that starts it's turn grappling you takes 1d8 Slashing and 1d8 Piecing damage

Improved Scale Armor

• Your Armor Class is 13 + Dex modifier
• You gain resistance to Bludgeoning, Piercing, and Slashing from Nonmagical Weapons
• Your base speed increases by 10 feet
• You have advantage on Dexterity checks and Dexterity saving throws
• You have advantage on Constitution saving throws

Bone Burst

Your mastery over your bones has reached its apex. You can use bone armor and bone armaments an unlimited number of times per day. 

In addition, you can perform a Bone Burst as an action. You deal 20d8 of Slashing, Piecing, or Bludgeoning damage in a 40 foot radius around yourself.  Once you use this feature, you can’t use it again until you finish a long rest.