Starting at 3rd level when you choose this concentration, whenever you strike a being with blood (as ruled by the DM) with your blood weapons, you regain 2 hp up to your maximum. This increases to 4 hp at level 6. If you score a critical hit against a living organism, you may regain half of the damage dealt (rounded up) as health.

Beginning at 6th level you gain the ability to drain energy from those recently deceased. If a being with blood (as ruled by the DM) has died within the last minute, you may spend 10 minutes draining its life force. You gain Hit Points up to one-fourth (rounded up) the creature's maximum Hit Points.

After 11th level, you have spent a long time honing your blood weapons and training to hit vital points of your enemies. Your blood weapon attacks score a critical hit on a roll of 19 or 20.

At 14th level, you gain the ability to drain from a short distance. You can rip blood from an enemy with blood (as ruled by the DM) and siphon it into your own pool. At a range of 20 or lower, make a ranged spell attack with constitution as the spell casting ability. On a successful hit, the enemy takes 4d10 necrotic damage. You gain half the health lost this way. (rounded down)

After 17th level, you have truly remade yourself in the vampire's image. Half of any necrotic damage you deal to others is added to your health (in addition to any it may add itself). You also regain 5 HP at the beginning of every turn as long as you have at least 1 Hit Point up to half of your total hit points.