Deathblade

All fighters are familiar with death, but few pursue it past defeating their foes.  Deathblades imbue their weapon attacks with Necromancy that allows them to use death itself as a weapon.

Bonus Proficiencies

Your studies of death and dying grant you proficiency with Poisoner's Kit and Medicine.

Felling Blow

Starting at 3rd Level when you choose this subclass, when you hit a creature with a weapon attack and it loses half or more of its remaining hit points, you may use your reaction to deal the same amount(s) and type(s) of damage to the creature.  You can use this feature no more than once per round.

Raise Foe

Starting at 7th level, while you are in initiative when you hit a hostile creature with a weapon attack and reduce it to 0 hit points or use Felling Blow to reduce a creature to 0 hit points, you may have it immediately regain HP equal to the damage it took.  It becomes an undead creature and has vulnerability to piercing, slashing and bludgeoning damage.  It obeys your commands to the best of its ability for as long as it has 1 or more HP.  While bound in this way the creature may not cast spells of level 1 or higher, use lair actions, legendary actions or actions that have a recharge.  If not given specific orders it takes the dodge action and uses its movement to move directly away from the last creature that damaged it. If the creature is reduced to 0 HP it ceases to be undead and loses the vulnerabilities it gained. It no longer obeys your commands. When you become incapacitated or leave initiative, the creature is immediately reduced to 0 HP.

You may use the feature a number of times equal to half your proficiency bonus and regain a use whenever an affected creature drops to 0 HP.

Deathly Attack

Starting at 10th level, while you have a creature under the influence of Raise Foe under your control you may add 1d6 Necrotic Damage whenever you hit a creature with a weapon attack. When you do, you may transfer a number of HP equal to the necrotic damage from yourself to a Raised Foe you control, or vice versa.

The amount of this damage increases to 2d6 at level 17.

Grim Solidarity

Starting at 15th Level, when you regain hit points from a spell, potion or your second wind feature, any Raised Foes you have regain the same number of hit points.

Keep Your Enemies Close

Starting at 18th level, when you exit initiative you may extend the effect of your Raise Foe ability on one humanoid for 24 hours. If you do, you lose HP equal to one third of its max HP.  The creature does not drop to 0 HP when initiative ends. It regains HP equal to difference between the HP that you lost and its current HP.  The creature cannot benefit from short or long rests. It no longer uses its movement to move away from you or your allies. You may use this ability again as an action any time before the 24 hours expire to extend the effect for an additional 24 hours.