Blood Wizard

Blood Wizards are wizards who can use blood, and their own vitality to cast, and empower their spells. It is a dark, and frowned upon practice, that only the most desperate, or demented individuals would do.

Life transference

You sacrifice some of your health to mend another creature’s injuries. You take 4d8 necrotic damage, which can’t be reduced in any way, and one creature of your choice that you can see within range regains a number of hit points equal to twice the necrotic damage you take.

 

Blood Channeling

When you choose this arcane tradition at 2nd level, you are able to use your own depleted life essence to channel your magical abilities. Whenever your current hit points are below your hit point maximum, you can use your own body as an arcane focus.

In addition, when casting a wizard spell that requires a costly material component, you can forego the component by taking 1d10 necrotic damage per 50 gp of the cost of the component (minimum 1d10). This damage can't be reduced in any way. If this damage reduces you to 0 hit points, the spell fails but the spell slot is not expended

Sanguine Burst

Also at 2nd level, you learn how to weave your life force into a spell you cast, boosting its intesity at the cost of your own vitality. Whenever you roll damage for a spell you've cast of 1st level or higher, you can choose to take necrotic damage equal to the spell's level to reroll a number of the damage dice up to your Intelligence modifier (minimum one). This damage can't be reduced in any way, and you must use the new rolls.

Bond of Mutual Suffering

At 6th level, you get Bond of Mutual Suffering which allows you to use your reaction (and blood) to damage an attacker. When you’re hit, you can use your reaction to force your attacker to suffer the damage they’ve caused to you.

Glyph of Hemorrhaging

Starting at 10th level, when you damage a creature with a spell, you can choose to curse that creature for 1 minute. While cursed in this way, whenever the creature is hit by an attack, it takes an extra 1d6 necrotic damage. At the end of each of the creature's turns, it can make a Constitution saving throw against your spell save DC, ending the curse on a succes.

This feature cannot be used against creatures that are undead or constructs. Once you use this feature, you can't use it again until you finish a short or long rest

Thicker than Water

Upon reaching 14th level, the blood that flows through your veins is empowered with arcane vigor that mends wounds and helps preserve your life. Whenever a spell or a magical effect causes you to regain hit points equal to your proficiency bonus.

In addition, while you are concentrating on a spell, you have resistance to bludgeoning, piercing, and slashing damage from nonmagical attacks