Order of the Dark Draught

By drinking an alchemical essentia, a draught crafted from the blood of vampires, members of this order are able to gain great power and incredible resilience. Though essentia does not confer the full curse of vampirism, several of the strengths (and a few of the weaknesses) of the vampiric condition are granted by this blasphemous draught. To create the essentia, the blood hunter and their allies must hunt down a vampire or vampire spawn and drain at least one gallon of the creature's blood. This blood is then mixed with a number of reagents and refined down to a single dose of essentia. Most blood hunters who join the Order of the Dark Draught hold a particular hatred for the undead. As such they take great pleasure in the idea of exsanguinating such abominations as a display of poetic justice.

Heightened Senses

Starting when you choose this archetype at 3rd level, you begin to adopt the improved abilities of a natural predator. You gain advantage on any Wisdom (Perception) checks that rely on hearing or smell. You also gain darkvision out to 60 feet. If you already had darkvision, you may add an additional 60 feet to your darkvision's range.

Bite of the Sanguisuge

Upon choosing this archetype at 3rd level, you gain the ability to draw sustenance and power from the blood of humanoids. You gain a bite attack, which you may use to target one willing creature, or a creature that is grappled by you, incapacitated, or restrained. This bite attack deals piercing damage equal to 1d4 + your Strength Modifier. This damage increases to 1d6 + your Strength Modifier at 11th level, and 1d10 + your Strength Modifier at 18th level.

When you make a successful bite attack, you may choose to use this feature to deal your crimson rite die in necrotic damage to the target. This damage is in addition to the bite's normal damage. If you choose to do so, you gain temporary hit points equal to the amount of necrotic damage dealt. You can use this feature to deal necrotic damage twice. You regain expended uses when you finish a short or long rest.

Damage dealt by your bite is considered magical for the purpose of overcoming damage resistance.

Resilience of the Damned

 Upon reaching 3rd level, you have resistance to bludgeoning, piercing, and slashing damage from nonmagical weapons, however you have vulnerability to radiant damage.

Predator's Step

At 7th level, your speed increases by 10 feet. You also can add 10 feet to your long jump distance and 3 feet to your high jump distance.

Spider Climb. You may use this feature to climb difficult surfaces, including upside down on ceilings, without needing to make an ability check. 

Charm

Starting at 11th level, you learn to tap into the hypnotic powers of your vampiric blood, allowing you to charm a target. To use this feature, you use your action to target one humanoid you can see within 30 feet of you. If the target can see you, the target must succeed on a Wisdom saving throw (DC equal to 8 + your proficiency bonus + your Wisdom modifier) or be charmed by you. The charmed target regards you as a trusted friend to be heeded and protected. Although the target isn't under your control, it takes your requests or actions in the most favorable way it can, and it is a willing target for your bite attack.

Each time you or your companions do anything harmful to the target, it can repeat the saving throw, ending the effect on itself on a success. Otherwise, the effect lasts 24 hours or until you are killed, are on a different plane of existence than the target, or you take a bonus action to end the effect.

You may use this feature once. You regain the ability to use this feature after completing a short or long rest. At 18th level you may use this feature twice before taking a short or long rest.

Vampiric Resistance

Beginning at 15th level, you’ve tapped into the power of vampiric blood to the extent that you can draw on supernatural resistance to harm. If you fail a saving throw, you can choose to succeed instead. Once you have used this feature you may not do so again until you complete a long rest.

At 18th level, you may use this feature twice before completing a long rest.

Legendary Predation

At 18th level, you have mastered the vampiric blood in your veins to the point that your speed and prowess become the stuff of legend. You can now take one of the following Legendary Actions. Only one legendary action option can be used at a time and only at the end of another creature's turn. You regain spent legendary actions at the start of your turn.

Move. You move up to your speed without provoking opportunity attacks.

Bite. You make one bite attack.