Hemoturgy (Black Bane)

You have manifested a tattoo that allows you to utilize ancient blood magic. Determine its appearance and the flaw associated with it. You gain the following benefits:

• Increase your Constitution score by 1, to a maximum of 20.
• You gain the ability to learn spells from the Blood Magic spell list. You learn the Crimson Contortion cantrip and Weapon of Blood spell from the sorcerer spell list. Neither spell counts towards your total spells known. Constitution is your spellcasting ability for any Blood Magic spells.
  • If you lack spell slots, you may instead cast Weapon of Blood at its lowest level. Once you cast it, you must finish a long rest before you can cast it again.
• You can increase the power of your spells at the risk of your own vitality. When you cast a spell with your Hemoturgy, you can use one of your Hit Dice to increase the spell’s level by 1. Immediately after you cast the spell, roll the Hit Dice. You take damage equal to the number rolled.

Your Hemotrugy may evolve once exposed to a blood curse. The nature of its evolution is reflected by the nature of the blood curse acquired. For example, an individual with Black Bane may manifest the following additional powers:

• At level 5, you can use your blood curse to nullify others' magic. You may use 3 of your Hit Dice to cast Counterspell or Dispel Magic at its lowest level without expending a spell slot. You may use additional Hit Dice to increase either spells' level by 1 per Hit Dice spent. Immediately after you cast either spell, roll the Hit Dice. You take damage equal to the number rolled.
• At level 10, you can channel your anti-magic blood and convert its essence to gain back some arcane power. As a bonus action, you may use your Hit Dice to regain a spell slot of a level equal to the Hit Dice spent. Immediately after you regain the spell slot, roll the Hit Dice. You take damage equal to the number rolled. You must use this spell slot prior the start of your next turn to cast a spell, otherwise the spell slot is lost. Also, when you use Hemoturgy to cast the Weapon of Blood spell it gains the following additional property:
  • When you hit a creature with an attack using this magic dagger, you may cast Dispel Magic at its lowest level without expending a spell slot at the same target as a free action.
• At level 15, you can suffuse your blood over your immediate surroundings to severe its connection from the Weave. You may use 8 of your Hit Dice to cast Antimagic Field without expending a spell slot. Immediately after you cast the spell, roll the Hit Dice. You take damage equal to the number rolled.
• At level 20, you can liquefy yourself into an entity of sentient blood. You may use 10 of your Hit Dice to True Polymorph yourself into a Blood Elemental. You may use additional Hit Dice to increase your Blood Elemental's Maximum Health by 10 per Hit Dice spent.  Immediately after you cast either spell, roll the Hit Dice. You take damage equal to the number rolled. If this damage would reduce you to 0 hit points, you may still transform. Once you return to your original form, you must make all Death Saving throws at Disadvantage until you receive magical healing. Additionally, your Blood Elemental form has the following property:
  • Creatures who share your space are under the effects of the Antimagic Field spell.