Order of the Crimson Fiend

This Subclass focuses on empowering elements of the blood hunter that are already there, like the brand and crimson rite mechanic. By nature there are healing and healing prevention elements worked in.

Crimson Armament

When you join this order at 3rd level, you learn to further control your Crimson Rite. When you use a bonus action to activate a Crimson Rite you don't need to be holding a weapon and can instead create a weapon of your choice, with an active Crimson Rite on it, out of blood, called a Crimson Armament. You are proficient with this weapon. If you create a weapon requiring ammunition in this way, the weapon creates it's own ammunition when firing that dissipates after being fired.

Additionally when activating a Crimson Rite you have the option of amplifying it which allows you to activate a second different Crimson Rite at the same time. When you do, you take necrotic damage equal to one roll of your hemocraft die. This damage can’t be reduced in any way. This causes the weapon to deal one instance of your hemocraft die for each of your active rights on it. The damage types of the rites are still counted separately. You can use this this effect when creating a Crimson Armament.

Furthermore you learn a new Crimson Rite called Rite of Blood which deals your hemocraft die in the damage type of your weapon.

[The visual representation of a Crimson Armament can be adjusted to fit your character more, just keep in mind that two different active Crimson Rites modify this visual even further.]

Life Through Blood

Starting at 3rd level, you learn to utilise the cost of your amplifying abilites and can gain resilience through blood sacrifice. When you amplify either a Blood Curse or invoke Crimson Rites, you gain Temporary Hit Points equal to the amount of damage taken.

Temporary Hit Points gained in this way can stack meaning damage taken from Amplifying a Blood Curse or casting a Crimson Rite do not subtract from the Temporary Hit Points as part of their costs of casting, instead always directly affecting your hit points. You cannot gain Temporary Hit Points from sources other than this feature and any magical healing you receive from other sources than your own features, while you have Temporary Hit Points, is halved. These THP last until you take a short or long rest and fade when you do.

In the event you would reduce yourself to 0hp from Amplifying a Blood Curse, casting a Crimson Rite or any self-harm feature, you fall unconscious and lose any remaining Temporary Hit Points.

[This can be represented by creating a barrier of some sort, having a pulsating second skin or simply redirecting effects]

Bloodbound Dominance

Upon reaching 7th level, you unlock a new way of controlling blood that confines your adversaries. A number of times equal to your proficiency bonus per long rest, when you hit a creature with an active Crimson Rite, take one hemocraft die of damage and you can apply one of these effects, even if the creature hit is immune to the rite damage type:

1. Bloodborne Restraint: The creature hit must make a Strength Saving Throw or be restrained for 1 minute. The DC equals 8 + your proficiency bonus and either your Intelligence or Wisdom modifier. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
2. Crimson Resurgence: If the creature hit is restrained, stunned or grappled it loses any immunities to the attacks crimson rites damage and instead becomes resistant against it or if it is resistant to the damage type it instead takes damage normally.
3. Hemoquidity: You gain resistance to the damage type of your active Crimson Rites until the start of your next turn. (A Rite of Blood grants resistance against non-magical slashing, piercing and bludgeoning damage)

[This has many ways of being portrayed: Manacles made out of blood, a solid prison around the creature...]

Brand of Reaping

Starting at 11th level, your Brand of Castigation reduces the healing capabilities of your foes as well as increasing your own at the same time. Creatures that you brand cannot regain hit points due a self heal regeneration feature. If a creature you've branded is healed by magic the healing received is halved, if it attempts to heal by consuming or using a magic item (e.g. potion of healing, ointment...) the brand converts the healing into poisong damage instead.

Additionally when you damage a branded creature you regain hit points equal to the crimson rite damage dealt to it.

[Flavor wise the Brand of Reaping controls the flow of life energy (more often than not, blood) of a creature and channels it directly into you]

Blood Curse of Vital Transfusion

At 15th level, you hone your hemocraft to not only heal yourself but sacrifice your own life in order to regenerate and heal the wounds of your allies. You gain the Blood Curse of Vital Transfusion for your Blood Maledict feature. This doesn't count against your number of blood curses known.

Blood Curse of Vital Transfusion
Prerequisite: 15th level, Order of the Crimson Fiend

As an action you restore health to another creature of your choice within 60ft. of you. The healing equals the amount of THP you possess. If you target a creature at 0 Hit Points you instead double the amount of any healing the creature recieves from this blood maledict.

Amplify. You take another two instances of your hemocraft die in damage (with the Amplify 3 in total) gain the THP and can add your Constitution modifier to the healing the creature recieves. The creature can use it's reaction to move half it's speed without triggering attacks of opportunity.

Once you use this Blood Curse, you must finish a long rest before you can use it again.

Additionally when you gain Temporary Hit Points due to self-inflicted damage you instead gain twice as much THP as damage taken.

[You either infuse another creature running on blood with your own or enhance the physicality of it or make it run like a puppet...]

Contracted Revival

Upon reaching 18th level, the Blood Hunter gains the ability to protect their fading life by forming an unwilling contract with another willing creature of their choice. This powerful feature, known as "Contracted Revival," grants the Blood Hunter a means of cheating death and achieving a form of immortality. Here's how it works:

When the Blood Hunter reaches 0 hit points and fails three death saving throws, or is killed outright by powerful means such as Power Word: Death, they can project their abilities and consciousness into another contracted creature within a range of 100 feet. If no suitable creature is within range or unwilling to accept the Contract, the feature fails, and the Blood Hunter dies as normal. The Contract remains in effect for a duration of 1 minute (10 rounds) or until the other contracted individual is also killed. In either case, the Blood Hunter's consciousness returns to their own body, which is then revived with 1 hit point. Furthermore, the Blood Hunter gains temporary hit points equal to half their maximum hit points, representing their revived vitality.

While the Blood Hunter's consciousness is projected into the contracted creature, they are unable to physically move or interact with other beings or utilize their own abilities and class features. They become effectively inactive, unable to use items or affect the world around them. However, they retain a sense of their surroundings and can experience any pain or sensations felt by the contracted creature.

 A contracted creature is empowered for the Conctracts duration and gains some of the blood hunters powers:

• Any weapon carried by the creature invokes the last active Crimson Rites you used, without the creature taking hemocraft damage. If the number of active rites and carried weapons don't overlap correctly you choose how they are assigned (e.g. 4 active rites on just 1 weapon does not work and you can instead choose two to activate on the contracted creatures weapon)
• If activated It gains resistance to the active Crimson Rites on its weapon.
• At the start of the creatures turn it regains hit points equal to half of the blood hunters level + their constitution modifier

This feature can only be used once, requiring the Blood Hunter to complete a long rest before they can activate it again.

Additionally, at 18th level, the Blood Hunter gains the ability to consume blood to mitigate the effects of normal aging, effectively eliminating death caused by old age. By nourishing themselves with the essence of blood, they obtain the necessary minerals, fluids, and energy to sustain their existence without the need for food, drink, or sleep. They still require 8 hours of light activity to gain the effects of a long rest.

[At this point you have become the Crimson Fiend itself and are able to live your life to the fullest and control your and foes blood as you please.]