Order of the Bloodletter

 Blood hunters that follow the Order of the Bloodletter focus on channelling the more destructive nature of hemocraft.  They are able to devastate a creature's vitality at the cost of their own, refresh their own health with the expiration of another, and even manipulate the blood of their foes at their most powerful. The hemocraft those of this path learn safeguard the user's health, while also burning through their vigour to empower their martial prowess, all for the sole goal of fulfilling the sadistic urge to inflict pain on others.

Rite of the Solvent

When you join this order at 3rd level, you learn the Rite of the Solvent as part of your Crimson Rite feature. When you activate the Rite of the Solvent, the extra damage dealt by your rite is acid damage. Additionally, while that rite is active on your weapon and you take acid damage, the first successful attack you make with this weapon by the end of your next turn has the bonus rite damage increased by an amount equal to your hemocraft modifier.

Blood Smite

 Beginning at 3rd level, you have learned to further sacrifice your life force to empower your strikes beyond their regular capabilities. Whenever you hit with a weapon that has a Crimson Rite active on it, you can choose to sacrifice a portion of your lifeforce to perform a blood smite.  You can choose to sacrifice a number of hit dice up to your proficiency bonus as a part of the same action and deal extra necrotic damage equal to the amount rolled. 

Barbed Resolve

 At 7th level, you have mastered the harmful effects of your sanguine magics, meaning that you cannot be reduced to 0 hit points by any damage caused by one of your blood hunter features. In addition, whenever you are reduced to 0 hit points, you can choose to instantly regain hit points equal to your hemocraft die plus your Constitution modifier. You can only regain hit points in this way a number of times per short or long rest equal to your Constitution modifier.

Brand of Exsanguition

Starting at 11th level, your Brand of Castigation prevents your quarry from recovering from their wounds effectively, and makes them susceptible to your hemocraft. Whenever the branded creature regains hit points, the number of hit points it regains is halved. Additionally, whenever you hit the branded creature with a weapon for which you have an active crimson rite, the creature cannot benefit from resistance and is treated as being vulnerable to the rite's damage.

Blood Curse of Haemorrhaging

 Starting at 15th level, you can cause blood to excessively leak from your foes, weakening their stamina and vigour. You gain the Blood Curse of Haemorrhaging for your Blood Maledict feature. This doesn’t count against your number of blood curses known.

 Blood Curse of Haemorrhaging

Prerequisite: 15th level, Order of the Bloodletter

 As a bonus action, you open the wounds and pores of a creature that you can see within 30 feet of you to allow blood to seep uncontrollably from their bodies for the next minute. For the duration of the curse, the cursed creature gains a level of exhaustion, has their movement speed halved, and their attacks deal 1d6 less damage (this can't reduce the damage below 1). The cursed creature can make a Constitution saving throw at the end of each of its turns, ending the curse on itself on a success.

 Amplify. For the duration of the curse, you can use an action on your turn to force the creature to make a Constitution saving throw, or gain another level of exhaustion on a failure (cannot increase levels above half of maximum exhaustion levels).

Lethal Disposition

 At 18th level, your sadistic combat style has reached its brutal limit, giving you the power to siphon the vitality of your foes and enhance your own ability in the face of death. When you successfully deal damage to a creature using a weapon with an active crimson rite, you can choose to regain hit points equal to the damage dealt by your rite. Additionally, when you have one quarter of your maximum hit points or less and you roll a hemocraft die, the roll of the die is maximum possible value.