Hemomancy

In the Shadowfell, the first vampire families who made it there gradually underwent an odd form of apotheosis. The dark ancient magic in that realm dramatically enhanced their existing powers and even blessed them with magical prowess and a loss of the weakness to sunlight or radiance, though it also pacified and sophisticated them. Their subsequent discovery of being able to use their blood to cast spells laid the foundation for what is known today as hemocraft, or hemomancy. The vampire nobility who pioneered this form of magic are called Nosferatus for male vampires and Lamias for female ones, and are often who hemomancers of today claim as their ancestors.

Hemomancers command blood magic with the same ease as breathing air thanks to their vampiric lineage. With constant bloodletting being a prerequisite for wielding it, they gradually develop a vitality rivaling that of even fighters across the planes. Through self sacrifice and sheer ferocity, these unique spellcasters can engage adversaries up close and strike with vicious fervor using crimson weapons made from their life force, a luxury seldom afforded to most other sorcerers.

Such power of course comes with equally dire risks. A hemomancer who doesn't temper their power with humanity might end up fully succumbing to primal vampirism and becoming more creature than person. Reckless use of hemomancy can also cause the spellcaster to exsanguinate. For those among them who know how to maintain a careful balance, hemomancers are assured that the power granted by their vampire ancestors vastly outweighs the risks.

Blood Warrior

Starting at 3rd level, you gain the following benefits as your vampiric magical blood awakens and flows through your veins:

You can use a bonus action to spend one Hit Die and conjure a melee weapon formed from your own blood which lasts an hour. Your hit points are reduced by the amount rolled, and you gain temporary hit points equal to the roll plus your sorcerer level. You can use your Charisma modifier instead of your Strength or Dexterity modifier for the attack and damage rolls of the weapon you form, and you are considered proficient with it. This weapon is considered magical for the purpose of overcoming resistances and immunities. 

Your hit point maximum increases by 6, and it increases by 2 whenever you gain another Sorcerer level.

As you delve deeper into hemomancy, your weapons become more potent. You have +1 to attack and damage rolls with your blood weapon at 6th level, +2 at 10th level and +3 at 14th level. Attacks with your blood weapon are considered melee spell attacks.

Bloodletter Vanguard

The blood from your Nosferatu or Lamia ancestor now offers you more advanced hemomancy abilities as your skill with the occult magic grows deeper. While you are wearing no armor, you can add your Charisma modifier to your Armor Class.

When you land a hit with your blood weapon, it leaves the creature bloodstained for one hour. While the creature is bloodstained, you have advantage on Intelligence (Investigation and Nature) and Wisdom (Perception and Survival) checks made to track it.

Once per turn when you hit a creature with your blood weapon, you may expend one sorcery point to inflict one of the following effects on that creature:

• Rhabdomyolysis: The creature must make a Constitution saving throw against your spell save DC. On a failed save, it has disadvantage on attack rolls, ability checks and must subtract 1d6 from all Strength-based attack rolls, saves and ability checks for one minute. The creature can repeat the save at the end of each of its turns, ending the effect on itself on a successful save.
• Osteonecrosis: The creature must make a Constitution saving throw against your spell save DC or take an amount of d8s in necrotic damage equal to half your sorcerer level rounded down.
• Spasticity: The creature must make a Constitution saving throw against your spell save DC or become restrained for one minute. The creature can repeat the save at the end of each of its turns, ending the effect on itself on a successful save.

Extra Attack

Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks.

Vampiric Scion

Your blood now strongly flows with the preternatural power of your lineage, which also causes you to develop some of their abilities, both magical and biological.

Vampire Fangs: Your canine teeth elongate and become natural weapons, which count as a simple melee weapon with which you are proficient. You add your Charisma modifier, instead of your Strength modifier, to the attack and damage rolls when you attack with your fangs. It deals 2d4 necrotic damage on a hit. Once on each of your turns when you attack with your blood weapon using the Attack action, you can make one fang attack as part of the same action.

When you attack with your fangs and hit a creature that isn’t a Construct or an Undead, you can regain hit points equal to the necrotic damage dealt. You can regain hit points in this way a number of times equal to your Charisma modifier, and you regain all expended uses when you finish a long rest.

Spider Climb: You gain a climbing speed equal to your walking speed. In addition, you can move up, down, and across vertical surfaces and upside down along ceilings, while leaving your hands free.

Deathly Transmutation: When you cast a spell that deals damage, you can spend 1 sorcery point to change the damage type to necrotic damage.

Hemocraft Sigil: As a bonus action, you can take 2d8 necrotic damage, then force one creature you can see within 60 feet of you to make a Wisdom saving throw against your spell save DC. On a failed save, the creature is branded by a transient sigil that causes it to be vulnerable to damage inflicted by your blood weapon until the start of your next turn. The necrotic damage dealt to you to activate this effect cannot be reduced in any way.

Hemoglobin Safeguard: Whenever you fail a saving throw, you can take 1d8 necrotic damage to spend 1 Hit Die or 1 sorcery point and reroll the save with a bonus equal to half your sorcerer level rounded down. You must use the new roll. The necrotic damage inflicted by this effect cannot be reduced in any way.

Occult Mastery

Starting at 18th level, you have now reached the pinnacle of hemomancy and thus have access to the ultimate technique that the Nosferatus and Lamias use against more troubling adversaries. As a bonus action, you can unleash the full power of your vampiric lineage as blood flows significantly faster throughout your body. For ten minutes, you gain the following benefits:

• Your blood weapon now deals additional damage equal to twice your Constitution modifier.
• At the start of your turn, if you are missing any hit points, you regain a number of hit points equal to twice your Constitution modifier so long as you have one hit point.
• You now have a 40-foot Emanation of dark energy centered on yourself, which counts as difficult terrain. A hostile creature that enters the area for the first time on a turn or starts its turn there must make a Wisdom saving throw against your spell save DC. On a failed save, it takes 4d10 necrotic damage and is frightened for 1 minute. The creature can repeat the save at the end of each of its turns, ending the effect on itself on a success.
• You gain immunity to necrotic and poison damage and gain temporary hit points equal to half the necrotic and poison damage dealt to you. You also gain a flying speed of 80ft and resistance to acid, cold, fire, lightning and thunder damage.

Once you use this feature, you can't use it again until you finish a long rest unless you expend 6 sorcery points to restore your use of it.