School of Sangromancy

Sangromancy uses the life force of beings contained in their blood to fuel its spells. The primary draw of playing a sangromancer is the ability to use HP as a resource to cast spells. This can be quite risky, especially at lower levels, so a budding sangromancer should keep good friends/meatshields around. At later levels, this is mitigated somewhat by the ability to cast Blood Siphon whenever casting a blood spell.

Sangromancy

As a blood mage, the power of your magic comes from your own (or other's) blood. Your spellcasting modifier is now based on your Constitution (Con) and you gain the Blood Siphon cantrip. You lose proficiency with intelligence saving throws and instead gain proficiency with constitution saving throws.

Starting at 2nd level when you choose this Arcane Tradition, you lose the ability to cast wizard spells using spell slots. Instead, you my cast any wizard spell you have prepared by sacrificing HP; Cantrips require no HP, but casting any spell of level 1 or higher requires you to take necrotic equal to the spell's level + 2. This damage cannot be prevented or resisted, and cannot be nonlethal. Additionally, ignore temporary hit points when taking this damage, and instead take it as if you had no temporary hit points. if you are reduced to 0 or fewer hit points by this damage, you automatically fail one death saving throw. Lastly, this damage does not cause you to make concentration checks.

If you would gain hit points from any spell you cast this way that is not a necromancy spell, you either gain that number of hit points or a number of hit points equal to half the damage you took to cast the spell, whichever is lower. You are still restricted to casting spells that a wizard of your level could normally cast.

When you take this feature, you gain access to the following spells as if they were on your class spell list:

Cantrip:
Blood Siphon
Blood Bolt
Blood Shield

1st Level:
Blood Purify
Blood Wound
Bloodrush
Bone Shards
Lifeblood Agglutination
Sacrificial Spear
Sanguine Analysis

2nd Level:
Blood Bond
Blood Curse
Blood Haze
Blood Mist
Blood Puppet
Blood Seal
Bone Spikes

3rd Level:
Blood Spear
Bone Spear
Corpse Explosion
Detect Life
Nash's Blood Armor
Shred Veins

4th Level:
Blight
Blood Slave
Eternal Rest
Evangeline's Bloody Grasp

5th Level:
Antilife Shell
Blood Oath
Contagion
Monstrous Polymorph

6th Level:
Adamantine Bones
Animate Blood
Call the Heart

7th Level:
Regenerate

9th Level:
Bonetwister

These spells are considered blood spells.

Note that items (such as scrolls or wands) or features (such as ritual casting) which allow you to cast spells without expending a spell slot do not require you to take damage, even if they are wizard spells.

Sanguine Fortitude

This Feature replaces the Arcane Recovery class feature. Sanguine Fortitude grants the following benefits:

• Each time you lose or fail to gain a spell slot due to the Sangromancy class feature, your maximum hit points increase by the level of the spell slot.
• You have advantage on Saving Throws to resist poison.
• Whenever you would gain hit points from spending hit dice during a short rest, you gain additional hit points equal to half your level (rounded down, minimum of 1).

Blood Transfusion

Starting when you gain this trait at 6th level, whenever you use your action to cast a blood spell that is 1st level or higher, you may use a bonus action to cast Blood Siphon.

Additionally,  you may use the blood of enemies, allies, dead bodies, or other sources of blood in order to cast spells. When using the blood of an unwilling creature to cast a spell, you must be within 15 feet of them, they must have less than half of their health left, and they must make a Constitution saving throw against your spell save DC. If they succeed, or if you attempt to target a creature with half or more of its hit points, the spell fails and they take no damage. If they fail, they take the necrotic damage of the spellcasting process and the spell then takes effect. When you reach level 16, this effect can target creatures that have half or more of their hit points but are not at full health, and may target creatures within 30 feet.

When using blood from a dead body, the creature must have died within the last 10 minutes. By using the blood from a dead body, you can reduce the damage you take from casting a spell by an amount equal to their number of hit dice(to a minimum of 1). You may not draw blood from the same body twice. You must be within 5ft of the body in order to use its blood.

 

If a creature or body does not contain blood (for example, most constructs), you may not use it to cast spells. 

Sanguine Aura

Starting at level 14, you gain the ability to more effectively use other's blood to cast spells. As long as a creature is within 5 feet of you, they have disadvantage on Constitution saving throws against you whenever you try to use their blood to cast a spell. This only applies to the process of casting the spell, not any Constitution saving throws that are needed as a result of the spell itself. At 17th level this aura increases to 10 feet, and at 20th level it again increases to 15 feet.

Sanguine Empowerment

When you gain this ability at 10th level, it has the following effects:

• Whenever you cast a spell, you may choose to increase the damage you take from using Sangromancy by 1d4. If you do so, that spell is considered a blood spell as it is cast.
• When casting a blood spell, you may either choose to increase your spell save DC by 1 or reroll any ones rolled for damage (these dice cannot be further rerolled).
• When casting a spell as a ritual, you may double its duration, up to a maximum of 48 hours.