Blood Queen Lana'thel

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

Regeneration. Lana'thel regains 20 hit points at the start of her turn if she has at least 1 hit point and isn’t in sunlight or running water. If she takes radiant damage or damage from holy water, this trait doesn’t function at the start of her next turn.

Demonic Bat Wings. Lana'thel can fly at a speed of double her movement speed.

Blood Mirror. Lana'thel reflects 100% of the damage done to her to the target nearest to her. The creature affected by this has a crimson red shine. If two or more creatures are equidistant to Lana'thel, whichever creature entered her presence last is affected.

Multiattack. Lana'thel makes two attacks, only one of which can be a bite attack.

Delirious Slash. Melee Weapon Attack: +9 to hit, reach 5 ft., one creature.Hit:  24 (4d4 +16) piercing damage plus the affected creature bleeds for 2d4 necrotic damage every turn for 3 turns.

Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one creature.Hit: 32 (4d6 +16) piercing damage plus 20 (4d8) necrotic damage. 

A creature affected by Lana'thel's bite attack suffers from "Essence of the Blood Queen". This curse allows a target to deal double damage and heal for 1/10th of damage dealt for 1 minute. Afterwards, a creature gains a thirst for blood, and becomes frenzied, requiring saturation from a humanoid. The only action they may take is to perform a melee bite attack, dealing 2d6+STR or DEX, and passing the "Essence of the Blood Queen" curse to that creature. Lana'thel heals for the damage dealt of this attack if performed on her.

If this hunger is not sated for 1 minute, they become charmed until Lana'thel's hit point is reduced to zero or she expends a bonus action to let them go of their curse. While charmed, a creature deals triple damage and heals for 1/5th damage.

Twilight Bloodbolt. Blood Queen Lana'thel casts a 17th level eldritch blast, but must direct each bolt at a different target if available.

Shroud of Sorrow. Blood Queen Lana'thel casts pulse wave.

Incite Terror. After suffering 10% of her hit points as damage, Blood Queen Lana'thel casts fear and flies 60ft into the air. While up in the air, she has access to this action. She lands after being dealt 10% of her hit points while being up in their air.

• Bloodbolt Whirl. Lana'thel casts 3 17th level eldritch blast with each bolt targeting a different creature if possible.

Blood Queen Lana'thel 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. She regains 1 spent legendary action at the start of her turn.

Pact of the Darkfallen. Blood Queen Lana'thel picks the 2 furthest creatures away from eachother and pacts them together. Each turn of any creature's that these two creatures spends further than 5ft away from eachother causes them each to take half of 4d8 damage. Once these creatures are within 5ft of eachother the spell ends. Only two creatures may be affected by "Pact of the Darkfallen" at once.

Swarming Shadows (Costs 2 actions). Blood Queen Lana'thel casts ravenous void.