Order of the Parasite

The practice of hemocraft is already seen as a dark and forbidden technique by most of the world, but it is a necessary weapon for blood hunters against the monsters that roam rampant among their homes. However, there is a ritual of hemocrafting that is seen as disturbing even to other blood hunters. Members of the Order of the Parasite undergo a ritual to birth and infect themselves with a parasite that dwells within their very bloodstream. It is not uncommon for members of this order to perish from the attempt, as most bodies do not like uninvited guests and tend to send themselves into high fevers to reject and repel the parasite.  Other times, members may go mad from the wriggling sensation they feel pulsing through their arteries, or even the occasional scratching inside the valves of their own hearts. Those that persevere this bonding find themselves with improved control of their hemocraft... and also find themselves an unusual ally in times of extreme peril.

Altered Arteries

The parasite within you has taken control of the potency and flow of your blood. 

If you must take damage from your hemocraft die, the damage you take from the roll is halved. 

In addition, once per turn when you deal damage to a creature with your crimson rite, you may roll an additional hemocraft die to the attack.

Symbiotic Relationship

The parasite within your bloodstream responds to your desires and can provide you with a boost of adrenaline and hysterical strength when you need it. 

Beginning at 3rd level, once per turn, you may roll your hemocraft die and add the number to an ability check or attack roll. When you do so, you must take damage equal to one roll of your hemocraft die, but it is not halved like your other hemocraft features. You may choose to use this feature after you roll, but before the DM decides whether your roll fails or succeeds.

Clutch Host

Beginning at 7th level, your parasite has gained greater abilities to protect its host. Once per turn when you are subject to a saving throw to take full or half damage, you may use this feature for your parasite to take control of your body temporarily to grant you advantage on the roll. If you succeed on this saving throw, you take no damage, but if you fail, you take half damage. 

Brand of Leeching

At 11th level, your blood has become the extension of your parasite. Whenever you hit the creature branded by this feature, you gain temporary hit points equal to a roll of your hemocraft die. If any of the temporary hit points gained from this feature remain at the beginning of your next turn, those temp hit points become hit points you regain if you are missing any of your hit points (if your hp is maxed out from this feature, the remaining temp hit points not added will remain until you take damage or receive other temp hp). 

In addition, the branded creature has disadvantage on all ability checks.

Blood Curse of Transfusion

Starting at 15th level, your blood curse can rip the blood out of other creatures for your own use. You gain the Blood Curse of Transfusion. This does not count against your number of blood curses known. 

The Blood Curse of Transfusion: 

As a bonus action, a creature you can see within 60 ft of you must make a constitution saving throw against your hemocraft dc or be infested by the power of your parasite. While infested, the creature takes all hemocraft damage that would normally be inflicted upon yourself, such as crimson rite activation, instead of you. This curse lasts for a minute or until you die.  

Amplify. The creature automatically fails the saving throw, the curse now lasts for 10 minutes, and you roll an additional hemocraft die when you attack the affected creature with your crimson rite. Once you amplify this curse, you may not do so again until you finish a short or long rest.

Pure Infection

At 18th level, your body has completely accepted the parasite within you and lets it roam without constraint. All of the features gained from this subclass that were limited to once per turn, may now be used infinitely. 

In addition, your parasite has learned how to work with your immune system. As a reaction whenever you are inflicted with any condition effect other than prone, grappled, or restrained, you may automatically end the effect.