Hemomancy

The archetypal Hemomancer is a practitioner of the dark, fiendish art of using your own life essence to bolster your spells in frightening ways. Many practitioners of the arcane arts categorize Hemomancy as the sister to Necromancy. Unsightly, and outright cruel to the victims of these magics, their ways are considered incredibly heretical in the eyes of clerics, paladins, and templars. These ways are typically learned through books created by devils from the Nine Hells, scattered across the prime material plane to attract young and curious magicians to vile ways.

Transfusion

2nd-level Hemomancy feature

At 2nd level, you have learned to convert your own life essence into arcane ability. As part of your short rest, you can perform a ritual to regain your lowest missing hit die, expending a spell slot of up to 6th level to regain a number of hit die equal to the expended spell slot's level.

You can use this feature a number of times equal to your Constitution modifier (a minimum of once). You regain all expended uses when you finish a long rest.

Blood Empowerment

2nd-level Hemomancy feature

Starting at 2nd level, you have learned to art of Hemomancy. You carve into yourself, dripping your own essence to bolster your spells with dark arts. When you roll damage for a spell attack, you can choose to spend one of your hit dice to deal as extra damage of the spell's type. You also take necrotic damage equal to half the amount rolled from your hit die, this damage cannot be avoided or reduced.

Additionally at 10th level, you can choose to use up to two of your hit dice to deal as extra damage of the spell's type.

Invigoration

6th-level Hemomancy feature

At 6th level, you have learned to enrich your own life essence. All hit die you gain starting at 6th level changes to 1d8 and all hit die you gain starting at 14th level changes to 1d10. This ability is not retroactive, and does not change previously gained hit die. Additionally, whenever you roll initiative and have no hit die left, you regain one of your highest hit die.

Rupture

10th-level Hemomancy feature

At 10th level, you have learned to manipulate other's blood to flow out of their bodies if they move. As an action, you can magically force a creature you can see within 60 feet of you to make a Constitution saving throw against your spell save DC. On a failed save, the creature takes 1d10 necrotic damage for every 5 feet of expended movement (excluding teleportation), and becomes blinded for 1 minute. The creature makes another saving throw against the effect at the end of their turn.

You can use this feature a number of times equal to your Constitution modifier (a minimum of once). You regain all expended uses when you finish a long rest.

Life Siphon

14th-level Hemomancy feature

At 14th level, you have learned how to steal the life energies out of a creature to bolster your own. As an action, you attempt to create a visible life tether to a creature you can see within 120 ft. of you for up to 1 minute or until your concentration ends (as if you were concentrating on a spell). The target creature must succeed a Constitution saving throw against your spell save DC or suffer 3d6 necrotic damage, healing yourself for half of the damage dealt. The creature has disadvantage on this saving throw if they are under the effects of Rupture. On each of your turns for the duration, you can use your action to deal the damage again to the target automatically, however adding an additional 1d6 to the damage up to a maximum of 10d6. The spell ends if you use your action to do anything else, if the target is ever outside the ability's range, and if it has total cover from you.

Once you use this feature, you can’t do so again until you finish a long rest or until you expend a spell slot of 3rd level or higher on it.