Arcliss, Crimson Matron

Amphibious. The red hag can breathe air and water.

Legendary Resistance (2/Day or 3/Day in Lair). If Arcliss fails a saving throw, she can choose to succeed instead.

Blood Sense. The red hag can pinpoint the location of creatures that aren’t Constructs or Undead within 60 feet of her and can sense the general direction of such creatures within 1 mile of her.

Magic Resistance. The red hag has advantage on saving throws against spells and other magical effects.

Speak with Beasts. The red hag can communicate with Beasts as if they shared a language.

Aura of Crimson Vigor. Creatures of her choice within 30 feet of Arcliss gain an additional 10 temporary hit points at the start of each of their turns. Enemies in the aura make concentration checks with disadvantage.

Coven's Oath. When Arcliss is within 60 feet of another Red Hag, she may use her reaction to take any damage directed at an adjacent hag instead. The damage is halved if absorbed this way. She may only use Oath once per round.

Multiattack. Arcliss makes two attacks: one Razorvine Whip attack and one attack with Burning Briar Staff.

Razorvine Whip. Melee Weapon Attack: +10 to hit, reach 15 ft., one target. Hit: 18 (3d8+5) slashing damage plus 7 (2d6) fire damage. On a hit, Arcliss may pull a creature of medium or smaller size 10 feet closer to her.

Burning Briar Staff. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 16 (2d10+5) bludgeoning damage plus 9 (2d8) fire damage. On a hit, the target must succeed on a DC 18 Constitution saving throw or be engulfed in burning vines, taking 5 (1d10) fire damage at the start of each of their turns for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Summon Red Thorn Elemental (Recharge 5-6). Arcliss channels primal fey magic to summon a Red Thorn Elemental in an unoccupied space within 30 feet. The elemental follows Arcliss's commands and uses the Red Thorn Elemental stat block. The creature disappears after 1 minute or until it's reduced to 0 hit points.

Spellcasting. The red hag casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 19):

At will: animal friendship, druidcraft, entangle

3/day: cure wounds, dispel magic, lesser restoration

1/day: control water, freedom of movement

Hand of Scarlet Fury. As a bonus action, Arcliss may cause her hands to ignite in crimson flames, dealing an additional 9 (2d8) fire damage with melee attacks for 1 minute. She can activate this ability once per short or long rest.

Gossamer Veil. Arcliss can turn invisible as a bonus action. While invisible and within dim light or darkness, she leaves behind an illusionary duplicate that occupies her previous space and performs mock actions. The veil lasts up to 1 minute or until Arcliss deals damage.

Arcliss can take 2 (3 in lair) 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. Arcliss regains spent legendary actions at the start of her turn.

Flame Lash. Arcliss makes one Razorvine Whip attack.

Floral Rejuvenation (Costs 2 Actions). Arcliss sheds sharp petals that restore 20 hit points to herself or an ally within 30 feet.