Essence Siphoner

Essence Plunderers are able to manipulate subtle threads of vitality, mental sharpness, physical steadiness, and instinctive reaction. When they strike at the right moment, they tear away a fragment of an enemy’s essence and weave it into their own form, strengthening their body or sharpening their mind for brief but powerful bursts.

Level 3: Level 3: Extricate

You gain a pool of Essence Dice (d6s) equal to your Proficiency Bonus. You regain all expended uses upon taking a Long Rest.

When you deal sneak attack damage to a creature, you can expend 1 Essence Dice to force the target to make a Constitution saving throw (DC = 8 + Proficiency Bonus + Intelligence modifier). Upon a failure, you steal a fragment of the creature’s essence and apply it to one of the following choices below. An ability score can be increased above 20 for the duration. Upon a success, a creature is immune to Extricate’s effect for the next 24 hours. The duration of this feature lasts until the end of combat.

Stolen Agility. Increase your Dexterity Score by an amount equal to the Essence Die roll. Your movement speed is increased by a number of feet equal to the die’s roll x 5. Your movement doesn't provoke attacks of opportunity. 

Stolen Vigor. Increase your Constitution modifier by an amount equal to the Essence Die roll. You gain temporary hit points equal to the roll on the die + your class level. 

Stolen Mind. Increase you Wisdom modifier by an amount equal to the Essence Die roll. You don't need advantage on the attack roll to use your Sneak Attack against a creature if you are within 5 feet of it, no other creatures are within 5 feet of you, and you don't have disadvantage on the attack roll.

Level 3: Level 3: Vital Sense

You gain the ability to read the shifting essence within other creatures. You gain proficiency in Insight (Wisdom) Checks. If you already have proficiency, you instead gain expertise.

Additionally, as a Bonus Action, you can identify whether a creature within 15 feet of you is Healthy, Injured, Weakened, Poisoned, Exhausted, or Magically Impaired. You do not discern the cause of the effect the creature is under. 

Level 9: Level 9: Essence Surge

When you deal sneak attack damage to a creature, you can expend one of your Essence Die to redirect the creature's essence forcefully back into them, causing a small explosion of energy. The target must make a Dexterity saving throw versus your Extricate DC or take 5d6 force damage and be thrown back 15 feet in a direction of your choice. If they succeed, they take half damage and are not thrown back.

Level 13: Amplified Essence

Your stolen essence mutates into more potent enhancements. When you use Extricate, you may spend 1 additional Essence Die to apply a stronger version of the infusion:

Overload Agility. Increase your Dexterity score by Essence Die + Proficiency Bonus. You also gain advantage on dexterity saving throws.

Overload Vigor. Increase your Constitution score by Essence Die + Proficiency Bonus. You gain resistance to bludgeoning, piercing, and slashing damage. 

Overload Mind. Increase your Wisdom score by Essence Die + Proficiency Bonus. Enemies have disadvantage on melee attacks against you.

Level 17: Level 17: Plunderer

When you kill a creature affected by your Extricate feature, you can now choose one skill, weapon, armor, or tool that they were proficient in and absorb it. You gain proficiency in what you chose. If you chose a skill or tool that you are already proficient in, you instead gain expertise. 

You can use this feature twice per Long Rest.