Blood Fiend

Legendary Resistance (3/Day). If the blood fiend fails a saving throw, it can choose to succeed instead.

 Magic Resistance. The blood fiend has Advantage on saving throws against spells and other magical effects.

Multiattack. The blood fiend makes two Claw attacks and one Bite attack, if possible.

Claw. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 11 (1d6 + 8) Slashing damage, and the target is Grappled (escape DC 21).

Bite. Melee Weapon Attack: +13 to hit, reach 5 ft, one willing creature or a creature with the Grappled, Incapacitated, or Restrained conditions. Hit: 12 (1d8 + 8) Piercing damage plus 2 (1d4) Necrotic damage. The target’s Hit Point maximum is reduced by a number equal to the Necrotic damage taken, and the blood fiend regains Hit Points equal to that number. The reduction lasts until reversed by Greater Restoration, or another powerful supernatural effect. The target dies if this attack reduces their hit point maximum to 0. A Fiend slain in this way rises the following midnight as a blood fiend.

Shape-Shift. The blood fiend shape-shifts into a Tiny bat (Speed 5 ft., Fly Speed 30 ft.), a dire wolf, nightmare or a Medium cloud of mist (Speed 5 ft., Fly Speed 20 ft. [hover]), or it returns to its blood fiend form.

While in non-mist forms, the blood fiend can’t speak. Its game statistics, other than its size and Speed, are unchanged.

While in mist form, the blood fiend can’t take any actions, speak, or manipulate objects. It is weightless and can enter an enemy’s space and stop there. If air can pass through a space, the mist can do so, but it can’t pass through liquid. It has Resistance to all damage, except the damage it takes from Radiant damage.

Spellcasting. The blood fiend can cast the following spells, using Charisma as its spellcasting ability (spell save DC 18):

At Will: Charm Monster, Detect Evil and Good, Detect Magic

3/Day Each: Darkness, Blight

1/Day Each: Divine Word, Hallow

Energy Drain. Constitution Saving Throw: DC 14, one creature the blood fiend has hit with a Claw attack in the last turn. Failure: The target gains one level of Exhaustion, and the blood fiend gains 5 Hit Points.

Resting Place (1/Day). Trigger: The blood fiend is reduced to 0 Hit Points by any damage type except for Radiant damage. Response: The blood fiend immediately uses Shape-Shift to become mist and attempts to Hide. After spending 1 hour hidden with 0 Hit Points, the blood fiend regains 1 Hit Point. If a Divine Word, Hallow, Dispel Evil and Good, or Banishment spell is cast on the area the mist is in, this effect cannot trigger.

Legendary Action Uses: 3. Immediately after another creature’s turn, the blood fiend can expend a use to take one of the following actions. The blood fiend regains all expended uses at the start of each of its turns.

Misty Escape. The blood fiend casts Misty Step, requiring no Material components and using the same ability as Spellcasting.

Swat. The blood fiend moves up to half its Speed and makes one Claw attack.