Bone Knight

A bone knight, or an osteoth, is a warrior that has
undergone an agonizing transmutation ritual,
granting them the ability to fully control their bones.
Naturally, this power is hideous and disfiguring, but
allows them to grow bone protrusions for weapons
and armor, changing their skeleton’s size and shape
at will. Mastering this ability is a feat of endurance
and creativity, but results in a fighter whose most
powerful weapon is not sheathed at their side, but
sheathed within their flesh.
Many fighters believe the osteoth ritual is a mere
myth, a flight of fancy traded around campfires,
but the process is indeed real, preserved among
moldering tomes and in the minds of deranged
wizards. With some resourcefulness, the procedure
can be replicated with the contents of any alchemist’s
lab, with a generous fatality rate of nearly half.

ADAMANT IVORY

Starting when you choose this archetype at 3rd level,
you can sprout plates of bone from your skin. While
you are not wearing any armor, your Armor Class
17. You can use a shield and still gain this benefit. At
higher levels, your Armor Class increases as shown
in the Adamant Ivory table.
Additionally, when you take bludgeoning,
piercing, or slashing damage, you can use your
reaction to shield yourself from the damage. Expend
a Hit Die, roll it, and decrease the damage taken by
the number rolled.
Adamant Ivory
Fighter Level Armor Class
3rd 17
5th 18
10th 19
18th 20

BONE BLADES

At 3rd level, you have total control over your skeletal
structure, allowing you to sprout blades of jagged
bone from each of your palms or wrists as you would
draw a weapon. These bone weapons have your
choice of the statistics of a longsword, shortsword,
or scimitar. You can’t be disarmed of these weapons.
You can retract these weapons as you would sheathe
a weapon.
Starting at 7th level, your blades count as
magical for the purpose of overcoming resistance
and immunity to nonmagical attacks and damage.
Additionally, once per turn when you hit a creature
with a bone weapon, you can expend a Hit Die to
extend the bone into the target. Add the Hit Die and
your Constitution modifier to the weapon’s damage
roll.

HARDY CONSTITUTION

By 7th level, your bones and their marrow have
grown more robust, granting you a formidable
healing factor. You regain your total number of hit
dice when you finish a long rest

RESTRUCTURE

Starting at 10th level, you can shift your skeletal
structure as an action to transform your appearance.
When you do so, you determine the specifics of the
changes, including adjusting your height and weight,
the shape of your face, the presence or absence of
your teeth, your posture, and so on. You can even
change your size from Medium to Small or vice
versa. The extent of these changes only extends
to your bone structure: you can’t change your skin
color, hair length, or clothing using this ability.

IMPROVED IVORY

By 15th level, your bones are as hard as steel and
as plastic as copper. When you expend a Hit Die to
use your Adamant Ivory feature to reduce damage
or use your Bone Blades feature to deal additional
damage, you can expend two Hit Dice at once. You
subtract the total from the bludgeoning, piercing, or
slashing damage you take, or add the total and your
Constitution modifier to the weapon’s damage roll,
respectively.

MASTER OSTEOTH

Starting at 18th level, when you roll initiative and
have fewer than half your Hit Dice, you regain 1d6
Hit Dice. Additionally, on your turn, you can expend
3 Hit Dice to regain a use of your Second Wind
feature, or expend 8 Hit Dice to regain a use of your
Action Surge feature (no action required).