Hemomantic Ancestry

May it be an ancestral curse, familial blessing, or even a far too pure understanding of your own body: your body itself is your arcane weapon. 

Spells may be boosted by the sacrifice of hit dice; spell slots can be regained by your own sacrifices, among other traits.

Hemomantic Spellcraft

Starting at 3rd level, you may ingrain a number of spells from the sorcerer spell list equal to your proficiency bonus; these spells do not count against your spells known, however casting them will have one of the following affects applied any time you cast it:

1. Spells that have an attack roll crit on a 19 or 20 on the die.
2. If a creature fails the saving throw of one of your spells: regain one hit die. If multiple creatures fail the same saving throw, regain hit dice equal to the number of affected creatures (limit prof. number of creatures).
3. Spells that effect friendly creatures grants you the ability to give the targeted creature (except self) a temporary hit points, equal to a number of hit dice you sacrifice, equal or less than your constitution modifier.
4. Spells that do not involve a creature can be cast as a ritual, replacing the material components with damage to you, equal to the spells level number of hit dice rolled.

Power Exchange

As a bonus action, you may use any one of these traits:

1. You may roll up to your level number of D6: take damage equal to the number rolled, and regain the number of dice rolled as hit dice. 

2. You may sacrifice up to five hit dice: regain a number of spells levels equal to the hit dice sacrificed (ie. 3 first level and a second level; one fifth level; etc.).

3. You may roll up to your level number of hit dice, regain the rolled total number of HP.

Level 3: Blistering Spells

Your spells are a part of your body, and you have a more intimate control over them. 

Whenever you cast a spell, and before you know if it hits or not, you may sacrifice a number of hit dice equal or less than your proficiency modifier to add that many D6 to your spell attack.

Level 6: Blood Guard

Your survival instincts have kicked into over drive, and you've learned how to use less necessary parts of your essence to protect yourself. 

Whenever a creature targets you for an attack, you may, as a reaction, expend up to two hit dice to reduce the attack roll. 

If you were to take damage, you may, as a reaction, make a constitution saving throw (DC equal to half the total damage). On a success, take half damage and regain one hit die.

Level 14: Bodily Control

You may now empower a larger list of spells. 

Any time you cast a spell requiring a saving throw that involves Dexterity, Strength, or Constitution, you may apply either of the following:

1. You may sacrifice two hit dice to reduce the targets saving throw, potentially forcing them to fail. 

2. If there are multiple creatures subject to the spell, you may sacrifice two hit dice, half the total (rounding up) and add it to your spell save DC.

3. If you're out of hit dice when casting a spell, you may roll a number of D6 equal to half your total hit dice; take the rolled number as damage and grant Disadvantage to the target. 

Enforced Weakness

You may, a profiency number of times per day, modify the saving throw of any spell you cast into one of the following:

Strength, Dexterity, or Constitution. 

Level 18: Unbound casting.

Whenever you cast a spell, you do not need to use a spell slot to cast it. Instead, you may expend a number of hit dice equal to the spell's level, and take the rolled damage.

Casting a spell this way is not considered a spell for the sake of counterspell, or similar abilities. Additionally, casting a spell this way requires no material components.