Enchant Vampiric Draught

You enchant a vial of Sacred Blood that you gathered from the casting of The Ritual of the Bloodletter into a potion known as Vampiric Draught.  The enchantment lasts until the potion is dispelled or triggered by creator drinking it.  Upon drinking it the Harrower can feel necrotic energy pulse through their body, healing 3d8+Int Modifier hit points and gains temporary hit points equal to 1d4+Int modifier.  Until the next long rest, the Harrower also receives Darkvision 60' and resistance to cold, bludgeoning, slashing, and piercing damage.  The Harrowers outer appearance takes on a pallid, gaunt look, giving them advantage on Intimidation checks.  The touch of a Harrower under the effects of the draught becomes a weapon at will, on a hit, the target takes 1d8 necrotic damage, and it can’t regain hit points until the start of your next turn. If you hit an undead target, it also has disadvantage on attack rolls against you until the end of your next turn.

Anyone else who drinks the Vampiric draught must make a Constitution saving throw against the creator's spell DC. On a failed save, the drinker falls into a deep enchanted sleep. If someone spends an action trying to rouse you, you can make a saving throw again at disadvantage.  The draught wears off after 12 hours or automatically if they take any hit points of damage; the character is incapacitated.