Avatar of Bhaal

Aura of Murder. As long as the avatar is not incapacitated, hostile creatures within 5 feet of it gain vulnerability to piercing damage unless they have resistance or immunity to such damage.

Blood Frenzy. While the avatar isn't blinded, it can see and has advantage on melee attack rolls against any creature within 60 feet of itself with fewer than half of its total hit points remaining, provided that the creature isn’t an Undead or a Construct. Total cover, heavily obscured areas, invisibility, and any other phenomena that would prevent sight do not affect this trait.

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

Sadistic Revelry. When a creature the avatar can see within 60 feet of it is reduced to 0 hit points, the avatar gains 15 temporary hit points and has advantage on all attack rolls, ability checks, and saving throws until the end of its next turn.

Sneak Attack. Once per turn, the avatar deals an extra 21 (6d6) damage when it hits a target with a weapon attack and has advantage on the attack roll, or when the target is within 5 feet of an ally of the avatar that isn't incapacitated and the avatar doesn't have disadvantage on the attack roll.

Multiattack. The avatar makes two Knife of Bhaal attacks.

Knife of Bhaal. Melee or Ranged Weapon Attack: +11 to hit, reach 5 ft. or range 30/60 ft., one target. Hit: 11 (2d4 + 6) piercing damage. If the target is a creature, it suffers a lingering wound that causes it to take 7 (2d6) piercing damage at the start of each of its turns. If the target is already wounded the damage dealt by the wound increases by 3 (1d6) each time the avatar hits with this attack. The wound ends if the target regains hit points or if a creature uses an action to stanch the wound, which requires a successful DC 19 Wisdom (Medicine) check.

The avatar can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The avatar regains spent legendary actions at the start of its turn.

Murderer's Blade. The avatar makes one Knife of Bhaal attack.

Shroud Self (Costs 2 Actions). The avatar magically turns invisible until the start of its next turn. This invisibility ends if the avatar makes an attack roll or makes a damage roll.

Shifting Nightmare (Costs 3 Actions). The avatar briefly transforms into the nightmarish Slayer, lashing out at all nearby. Each creature within 10 feet of the avatar must succeed on a DC 19 Dexterity saving throw or take 21 (6d6) piercing damage.