Blood Mage

Your blood itself flows with magic, whether caused by an early life encounter with a vampire or a mutated inheritance of more traditional arcane magic. Your blood is the source of all your power, and you find ways to enhance your spells using your blood, and the blood of others, as a resource.

Arcane Constitution

You have 1 more hp per sorcerer level,  you have resistance to poison damage, and you have advantage on saves against poison and disease.

When you cast a Blood Mage spell or use a Blood Mage class feature you can choose to spend hp equal to double the spell level (1 for cantrips) bypassing temporary hp, resistance, and immunity to amplify the spell, gaining a bonus to the damage roll equal to your CHA modifier. The damage bonus can only be applied if the spell requires either an attack roll or saving throw. If a spell has more than one attack roll an additional hp must be spent per additional attack roll to gain the bonus. If this damage would knock you unconscious the full effect takes place first, and if the effect would heal you above 0 hp you do not lose consciousness. 

Starting at level 2 when you spend hp to amplify a spell of 1st level or higher you can choose to instead cast the spell as if you expended a spell slot 1 level higher than you actually used instead of taking the damage bonus. You can amp spells in this way even if you are using a spell slot higher than the minimum.

Crimson Thirst

Starting at level 6, you can spend 2 sorcery points and target a number of creatures that have blood within 30 feet equal to your charisma modifier (minimum 1), they each take 2d8 necrotic damage (half on successful CON save) and you heal for half of the damage dealt. Once you use this ability you cannot do so again until you finish a long rest. You are able to amplify this ability using your Arcane Constitution feature by spending 4 hp.

At level 11 you instead deal 4d8 damage with this ability, and at level 17 you deal 6d8 damage with this ability.

In addition, you may reattach any severed limbs within 24 hours of it being removed. This process takes a short rest where you must expend at least 1 hit die or a long rest.

Hemophilia

Starting at level 14, you can spend 3 sorcery points to target an area within 60 feet as a bonus action, all creatures within 15 feet of that space make a CON save. If they fail, the next time they take damage within a minute they are counted as vulnerable to that damage type. If they were immune or resistant to that damage type they instead take full damage from the attack but are not vulnerable. You can amplify this ability using your Arcane Constitution feature by spending 6 hp. Once you use this feature you cannot use it again until you finish a long rest.

You have gained enough control over your body that you age half as quickly as normal for your race, you no longer show physical signs of aging and are resistant to magical aging effects and necrotic damage.

Sanguine Mastery

At level 18 you have mastered the magic in your blood, granting you the following features:

All healing you receive is increased by 50%, you halt aging entirely and appear to be in peak condition at your prime age. You are completely immune to magical aging, disease, poison, and necrotic damage.

When a creature with blood within 60 ft of you dies you can use your reaction to absorb their blood, regaining 2 sorcery points and 4 hit points (before applying the 50% increased healing that also comes from this feature).