Sanguimancy

You have learned to tap into the power of blood sacrifice to fuel and augment your spells. You gain the following abilities:

• Blood magic. Once per turn, when you cast a spell of 5th level or lower, you may choose to spend a number of hit dice instead of a spell slot. The number of hit dice spent equals the level of the spell slot that would have been used to cast the spell. Spells cast in this way are considered to be using your own life-force as an arcane focus.
  Alternatively, when you cast a spell using a spell slot, you may choose to spend up to five hit dice to cast the spell at a higher level, spending one hit die for each level above the spell's original level. You may not cast a spell at a higher level than you would normally be able to using a spell slot.
  Cantrips are considered to be spells of 1st level for all purposes of the feat.
  When you expend at least one hit die to cast a spell or cantrip in this way, you add your Constitution modifier to your spellcasting ability modifier when determining the spell's attack bonus and spell save DC.
  Roll all hit dice spent in this way. Your hit points maximum is decreased by the amount rolled. You cannot use spent hit dice to recover hit points during a short rest, and you recover all spent hit dice when you finish a long rest.

• Blood Sacrifice. When you cast a spell as a ritual, you may use blood that is no more than 10 minutes old as a consumable material component, replacing any or all material components that do not exceed a value of 50gp, with the exception of materials specifically requires by the spell's description.
  Optional Rule. It is possible that the blood of rare creatures, such as dragons, fiends, or powerful fey, may have an innate aptitude for certain ritual spells. Or, they may have variant properties, adding strange, chaotic and potentially unpredictable effects to your magic. DMs and players who are feeling creative may work together to find new ways to feature the dark power of sacrifice within ritual magic.

• Augmented Blood-casting. When you take this feat, you choose two options from an extended metamagic list. You may exchange one of your choices for a new one when you finish a long rest. You may only apply one augmentation to a spell you cast on your turn. If an additional feat or class option gives you access to sorcery points or another means by which to augment your spells, you may not do so in conjunction with the feat.