Blood Armor

You summon a protective layer of blood around your body, blocking attacks with your own essence and granting you resistance to piercing, slashing, and bludgeoning damage for the duration of the spell. While the spell is active, any creature that makes a melee attack against you takes 1d6 necrotic damage.

Additionally, at the end of the spell's duration, you take 1d6 necrotic damage for each time the spell prevented damage, as the blood used to protect you returns to your body.