Order of the Thrall

Your curse either forced or by choice now leaves you like many others at the mercy of bloodsucking demons. A vampire's thrall, the position of a slave, with all the horrors you have already been through it is no wonder you embarrassed your horrible cursed for the purpose of revenge. Climb from the weakness of the thrall to the powers of a real vampire and though sustaining oneself will cause you to devour blood yourself, with all the strength of the demons who kept you in chains the price is readily worth the risk.

The Order of the Thrall is a bit of an underground grouping, seeking out your fellow enslaved, these hunters have either worked their way in or found strength in their binding similar to you. Trained underground with others who plan for freedom and revolution, you too seek to become a vampire hunter without the use of holy water or silver cross, no through the power of the very curse they gave you is how their life will end. Yet, these Blood Hunters must be careful not to lose themselves, they still must drink and feast upon mortals for their blood, and such a exquisite taste can lead one astray - not to mention the luxuries that come with being a vampire can cause some to stay, but if that vengeance continues to fester such temptations mean nothing.

Vampire's Curse

When you join this order at 3rd level, the curse gifted to you begins to spike. As a benefit through your new powers, as long as the character remains in dim light or lower, this Blood Hunter regenerates their proficiency in health every turn as a quick heal. Though your mortal side is still prevalent when in Sunlight or Running Water - this Blood Hunter takes 2 Radiant or Acid Damage if they don't wear either waterproof clothing in running water or perhaps some sort of wide sun hat to hide from the light, but no matter what protection the Blood Hunter can not add proficiency to any role thanks to the interference. Than finally as an optional rule, thanks to the strangest part of your curse, you can't seem to enter an establishment of any sort without getting permission from someone within. 

The Shapechanger

Upon reaching 7th level, the powers of a vampire swell even further as the supernatural power to shift one's form begins to take hold. Now If the Blood Hunter isn't in sun light or running water, it can use its action to Polymorph into a Tiny bat or a Medium cloud of mist, or back into its true form. Anything the character is wearing transforms with it, but nothing it is carrying does. It reverts to its true form if it dies.

While in mist form, the Blood Hunter can't take any Actions, speak, or manipulate Objects. It is weightless, has a flying speed of 20 feet, can hover, and can enter a Hostile creature's space and stop there. In addition, if air can pass through a space, the mist can do so without squeezing, and it can't pass through water. It has advantage on Strength, Dexterity, and Constitution Saving Throws, and it is immune to all non magical damage, except the damage it takes from sunlight

Rite of the Fangs

Upon reaching the 11th level, you can harness the blood-starved Rite of the Fangs.

Rite of the Fangs Your rite damage is necrotic type. After dealing damage against a foe with actual blood, half the rite damage dealt is healed.

Misty Escape

Upon reaching 15th Level, When the Hunter drops to 0 Hit Points, the Blood Hunter can choose to transform into a cloud of mist (as in the Shapechanger trait) instead of Falling Unconscious, provided that it isn't in sunlight or running water. If it can't transform, ignore this ability

While in mist form, the Blood Hunter can't revert to its regular form, and it must reach the location of the last long rest within 2 hours or transform back laying at the side of the road. If the character makes it, they stay Paralyzed for an hour where the Hunter can wake back up with 1 hit point and continue to regenerate.

Charms of the Night

At 18th level, you begin to obtain the powerful charms of the Vampire, first off the Blood Hunter gains the ability to use a powerful charm, using a spell save DC with their charisma bonus. If the target can see this Blood Hunter, the target must succeed on a Wisdom saving throw against this magic or be charmed - and it counts as a non-magical effect so goodbye anti-charms. The charmed target regards the character as a trusted friend to be heeded and protected. The target isn’t under their control, but it takes the Hunter's requests and actions in the most favorable way and lets the Blood Hunter get one clean hit for free.