Personal Blood Magic

 Blood Magic. The dreaded secrets of it are as incredible as they are terrifying, allowing a sorcerer to access overwhelming power—if they're willing to pay the crimson price. As a practitioner of these grisly arts, you do not favor a traditional bloodline, and instead focus on the ability to augment spells through the perilous spilling of blood. One who dabbles in these taboo techniques is most commonly known as a hemomancer or hemocrafter.

Many people confuse Blood Arcana with necromancy, but the truth is that the two practices are opposites. Necromancers harness the power of death, whereas hemomancers harness the power of life. A hemomancer is similar to a cleric focused on healing, but employs their practices in reverse—whereas the cleric uses their magic to restore life, a hemomancer does the unthinkable, and instead consumes life to empower their magic.

 

Resilient blood

At 1st level, your blood is infused with resilient life energy, allowing you to draw more from that wellspring. You have one bonus sorcerer hit die. You gain another bonus hit die at sorcerer levels 4, 8, 12, 16, and 20.

In addition, you have advantage on saving throws made to resist poison, and you regain an additional 1d4 hit points for every hit die you spend after finishing a short rest. 

Bloody Exchange

Starting at 1st level, you gain the ability to cast beyond your normal limit by sacrificing the vital life force inside of you. 

When you cast a sorcerer spell with a spell slot, you can choose to expend a sorcerer hit die (d6), taking damage equal to the roll, and empowering the spell. Making it a Blood Spell with one of the three following effects (your choice):

If the spell has a more powerful effect when you cast it at a higher level, you instead cast the spell as if you had used a spell slot of one level higher (to a maximum of 9th level).
If the spell deals damage, it ignores damage resistances.
If the spell slot used is 4th level or higher, you restore a 1st level spell slot.

You also gain the ability to expend your life force in the pursuit of more directly powerful magic. As a bonus action on your turn, you can choose to expend any number of hit dice you have, gaining 1 sorcery point for each hit die expended. This feature cannot increase sorcery points beyond the maximum for your level.
The damage you take as part of this feature ignores resistance and immunity, and does not require you to make a Constitution saving throw to maintain your concentration. You can use this feature a number of times equal to your charisma modifier (a minimum of once). You regain any expended uses when you finish a long rest.

Sanguine Rebuke

At 6th level, you gain the ability to cast spells when you are wounded, turning the blood spilled from your veins into magic as you bleed. When you take slashing, bludgeoning, or piercing damage, or damage from a Blood Spell, you can spend 2 sorcery points and use your reaction to cast one spell that would normally require an action or bonus action to cast. You cast this spell after you take the damage.

Ruby Withering

Starting at 14th level, you learn how to use the blood already spilled from you to further strengthen magic beyond its limits. When you reach half your hit points or lower, you gain a +3 bonus to AC. When you have this bonus and roll damage for a sorcerer spell that you cast, you add your proficiency bonus as bonus damage. In addition, when you damage any creature with a Blood Spell in this way, you may choose to prevent all affected creatures from regaining hit points until the end of their next turn.

Gore Storm

At 18th level, you learn how to force your magic into the body of a mortally wounded creature with such ease and force to create an explosion of magic. When you deal damage to a creature and reduce it to 0 hit points, you can spend 2 sorcery points to cause the creature to explode violently. The target fails one death save automatically. Each creature within a 15 foot sphere centered on the target must make a Constitution saving throw. On a failed save a creature takes 7d6 necrotic damage. On a success, a creature takes half damage. For the purpose of any other sorcerer class feature, you treat each explosion as if it were a Blood Spell.