Vampire Thrall

Regeneration. The thrall regains 10 hit points at the start of its turn if it has at least 1 hit point and isn't in sunlight or running water.

Multiattack. The thrall makes two attacks, one with its bite and one with its claws.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one willing creature, or a creature that is grappled by the thrall, incapacitated, or restrained. Hit: 6 (1d6 + 3) piercing damage plus 7 (2d6) necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and the thrall regains hit points equal to that amount.

Claws. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) slashing damage.