Sacrificial Domain

Some adventurers gain power through study. Some gain power through a deity. You gained your power through sacrifice. You hurt yourself to hurt others. Or hurt yourself to heal others. Regardless, you're hurting yourself, a lot.

Bonus Proficiency

When you choose this domain at 1st level, you gain proficiency with martial weapons.

Disciple of Blood

Also starting at 1st level, your healing spells are more effective. Whenever you use a spell of 1st level or higher to deal damage, you may take 1d6 necrotic damage to deal an additional 1d8 radiant damage

Channel Divinity: Siphon Blood

Starting at 2nd level, you can use your Channel Divinity to draw the blood from your enemies.

As an action, you can siphon blood from a wounded target. The target must make a constitution saving through, and if it fails, you gain health equal to the amount of their maximum health minus their current health, divided by two. The target also takes 1d6 necrotic damage. You can’t use this feature on an undead or a construct. You cannot target the same creature more than once per encounter.

Sacrificial Healer

Beginning at 6th level, the damaging spells you cast on others heal you. When you cast a spell of 1st level or higher that damages creature other than you, you regain hit points equal to 2 + the spell’s level.

Necrotic Strike

At 8th level, you gain the ability to infuse your weapon strikes with sacrificial energy. Once on each of your turns when you hit a creature with a weapon attack, you can sacrifice your own blood, dealing 1d8 necrotic damage to yourself, causing the attack to deal an extra 2d8 necrotic damage to the target. When you reach 14th level, the extra damage increases to 3d8.

Blood Frenzy

Starting at 17th level, you can, as an action, you can go into a blood frenzy for one minute. At the start of your turn for the next minute, you take 4d6 necrotic damage. Every attack you hit within that minute heal you for half the amount of damage done. Every attack also has a +2 on attack rolls, and an additional 1d10 of damage.