Sorcerous Origin: Blood Magic
Power runs in the blood of every sorcerer, but this is especially true for blood mages, who are able to draw strength from (and manipulate) the latent magical essence within all living beings. This rare ability is often unfairly labelled as evil and an affront to civilised spellcasters. In reality, a blood mage is just as likely to use their power for good or ill as your average person with a sword.
The manifestation of their power is subtler than other branches of sorcery, with early signs such as increased healing capabilities, rather than flashy pyrotechnics or spatial rifts.
Potent Metabolism
From 1st level, your magically enhanced blood accelerates your natural healing capabilities, allowing you to take more punishment in a fight. Your hit point maximum increases by 1 for each level you take in this class. Additionally, your maximum number of Sorcerer hit dice increases by 1.
Sanguine Malediction
When your blood flows, so too does magic, often with harmful consequences. From 1st level, when a creature you can see damages you with an attack or spell, you may use your reaction to force it to make a Constitution saving throw. On a failure, it takes necrotic damage equal to half the damage you took.
You may use this feature a number of times equal to your Charisma modifier, and you regain all expended uses on a long rest.
Blood Magic
From 6th level, you gain access to your full range of sorcery, harnessing your own life force for greater magical potential. When using your Font of Magic or Metamagic features, you may choose to sacrifice hit points instead of expending any sorcery points. You must expend 6 hit points per sorcery point replaced in this way.
Magic is taxing, even on your body. When you spend hit points in this way, your hit point maximum is reduced by the same amount until the end of your next short or long rest.
You must choose to either use hit points OR sorcery points, for instance you cannot spend two sorcery points and 6 hit points to use Heightened Spell; you must either spend three sorcery points or 18 hit points.
Untapped Potential
At 6th level, you gain a new Metamagic option from that feature, which does not count against the number of options you are allowed to pick. You may only use this Metamagic option by spending hit points as per your Blood Magic feature. If you later gain that Metamagic option by choosing it from the feature normally, you may choose a new one to replace it as your Untapped Potential.
Reconstitution
At 14th level, the magic in your blood feeds on external power to improve your healing capabilities. Whenever dice are about to be rolled to restore hit points to your character via magical means (such as a spell or Potion of Healing) you may use your reaction to forego rolling, instead treating all the dice as having rolled their maximum values.
Ritual of Sacrifice
At 18th level, you learn to use the blood of other creatures to empower your magic. If you are within 5 feet of a deceased creature’s body when you use your Blood Magic or Untapped Potential features, you may draw the necessary hit points from a pool totalling that creature’s maximum hit points instead. Magic works best with the blood it was born from however, and all hit point costs are doubled when paying them this way. You may not use the corpse of a creature that did not possess blood, such as a skeleton or iron golem.