Nightstalker

Whether directly taught by the entities, learning through observation and study, or being born with the capabilities, nightstalkers call upon the power of forces that manipulate others and drain vital essences, at times utilizing blood magic or other forms of necromancy to become what they are. Although these beings are often of the affiliated with such entities that would feed upon the body or soul, they can be found in various other forms, perhaps serving as agents of a fiend or vampire, or even serving to fight those very same beings.

Siphon Focus

3rd-level Nightstalker feature

You have learned to harness the power of a strong being, most commonly a vampire or an incubus or succubus. While the undead may hunger for physical form such as flesh or blood, fiends deal in more spiritual matters, including thoughts or the soul.

When you choose this archetype at 3rd level, choose either necrotic damage or psychic damage. You have resistance to this damage type, if you did not already.

Necrotic Siphoning

You have resistance to necrotic damage.

Psychic Siphoning

You have resistance to psychic damage.

Stealthy Drain

3rd-level Nightstalker feature

At 3rd level, when able to perform a sneak attack, roll half the number of Sneak Attack dice for your level (round up), and deal that amount of damage as your Siphon Focus (as chosen when you chose this archetype), which also reduces the target's maximum hit points by the same amount as the additional damage dealt. The amount dealt is returned you as temporary health points, as the life force of the creature is drained into you.

You can use this feature a number of times equivalent to your proficiency modifier, and regain all expended uses after you finish a long rest.

Drain the Body

At 3rd level, when able to perform a sneak attack, roll half the number of Sneak Attack dice for your level (round up), and deal that amount in necrotic damage, with the target's maximum hit points also reducing by the same amount as the necrotic damage. The amount dealt is returned you as temporary health points, as the life force of the creature is drained into you.

You can use this feature a number of times equivalent to your proficiency modifier, and regain all expended uses after you finish a long rest.

Drain the Soul

At 3rd level, when able to perform a sneak attack, roll half the number of Sneak Attack dice for your level (round up), and deal that amount in psychic damage, with the target's maximum hit points also reducing by the same amount as the psychic damage. The amount dealt is returned you as temporary health points, as the life force of the creature is drained into you.

You can use this feature a number of times equivalent to your proficiency modifier, and regain all expended uses after you finish a long rest.

Siphoned Ability

9th-level Nightstalker feature

Your strike drains not only the vitality, but also the capability of its victim for a short time. After draining a target with Stealthy Drain, select an ability score. The target has to make a Constitution saving throw against 8 + your proficiency bonus + your Charisma modifier. If they fail, you have advantage on saving throws with that score, and the target has disadvantage on ability checks and saving throws with that same ability score, both until the end of your next turn.

Reaving Dash

13th-level Nightstalker feature

As a bonus action, you can teleport to a space within 30 feet of you.

If you drain necrotic energy, you transform into a cloud of mist and moving to that space. If you drain psychic energy, you transport yourself to the Ethereal Plane as per the blink spell, and reappear in the space chosen.

Treat any physical obstacles as difficult terrain, with exception of living beings. If you travel through a being aside from a construct, elemental, or undead, deal 1d6 of your associated damage type, and add that amount of damage to your own hit points, up to a maximum of your proficiency bonus multiplied by your Dexterity modifier, with a minimum of 2. If the amount of hit points exceeds your current maximum hit points, the remainder is provided as temporary hit points.

Once you use this feature, you can’t do so again until you finish a long rest.

Jaunt of the Fiend

As a bonus action, you can teleport to a space within 30 feet of you. You move into the Ethereal Plane as per the blink spell, and reappear in that location.
Treat any physical obstacles as difficult terrain, with exception of living beings. If you travel through a being aside from a construct, elemental, or undead, deal 1d4 psychic damage, reduce the targets by that amount, and add that amount of damage to your own hit points, up to a maximum of your proficiency bonus multiplied by your Dexterity modifier, with a minimum of 2.
Once you use this feature, you can’t do so again until you finish a long rest.

Mist of the Vampire

As a bonus action, you can teleport to a space within 30 feet of you. You transform into a cloud of mist and fly to that space, visible to others as a cloud of what appears to be blood.

Treat any physical obstacles as difficult terrain, with exception of living beings. If you travel through a being aside from a construct, elemental, or undead, deal 1d6 necrotic damage, reduce the targets by that amount, and add that amount of damage to your own hit points, up to a maximum of your proficiency bonus multiplied by your Dexterity modifier, with a minimum of 2.

Once you use this feature, you can’t do so again until you finish a long rest.

Hearts and Minds

17th-level Nightstalker feature

You are able to invoke the charming power of the entity you imitate. As an action, choose one target that you can see within 30 feet. The target must make a Wisdom saving throw against a DC of 8 + your proficiency bonus + your Charisma modifier. If they fail, they are charmed for 1d4 hours. A charmed target regards you as a trusted friend, and will fulfill any orders given to the best of their ability.

They will also willingly take up the damage of Stealthy Drain, though any other damage will allow them to attempt the Wisdom saving throw again.

While you may not use this ability on more than one target at a time, you may use it an amount equal to your Charisma modifier, and regain all uses after a long rest.