Andariel, Maiden of Anguish (Demolith)

Demolith Subtype. Andariel has the "(demolith)" tag, which has no rules of its own, but is a tag that affects her in the same way that it would affect a demon or devil.

Semi-Immortal Nature. Andariel can't die of old age unless affected by magic of a spell of 7th level or higher and doesn't require food, drink, air, or sleep.

Legendary Resistance (4/Day). If Andariel fails a saving throw, she can choose to succeed instead.

Greater Magic Resistance. Andariel automatically succeeds on saving throws against cantrip spells, and has advantage on saving throws against all other spells and other magical effects.

Magic Weapons. Andariel's attacks are magical.

Maiden of Anguish (Unshackled Only). Whenever Andariel takes damage that isn't radiant, fire, or force, she automatically regains 14 (4d6) hit points. Additionally, while within the Realm of Anguish within the Burning Hells, every time a creature with an Intelligence score of 9 or higher fails a saving throw against any of Andariel's abilities, she regains 11 (2d10) hit points and has advantage on Charisma checks and saving throws for 1 minute.

Telepathic Bond. Andariel ignores the range restriction on her telepathy when communicating with a creature she has charmed. The two don't even need to be on the same plane of existence.

Shapechanger. Andariel can use her action to polymorph into a Small or Medium humanoid or fiend, or back into her true form. Other than her size, speed, and whatever attack options the form hs that she does not, her statistics are the same in each form. Any equipment she is wearing or carrying isn't transformed. She reverts to its true form if she dies.

Sandscorched Shackles. As long as Andariel is at 260 hit points or more, due to the gigantic shackles that chain her limbs, she has the following affects: She cannot make melee attacks besides with her Chain-Skull or Dragging Chains, her speeds are halved, she has disadvantage on saving throws, and she cannot use her Shapechanger ability in any way.

Dust Cloud. As long as Andariel is on the Material Plane and not underground, she always starts combat by creating a massive dust cloud around herself and whoever she is fighting. The cloud is roughly 180-ft wide and 60-ft tall, with a 60-foot wide area of unmarked space within the middle of the cloud where Andariel faces her opponent(s).

Melee Venom. Whenever Andariel hits a creature with a melee attack the deals poison damage, or a creature fails a saving throw against one of her abilities that deals poison damage by 4 or more, that creature has disadvantage on saving throws against being poisoned for 1 minute.

Multiattack (Unshackled Only). Andariel makes two melee attacks and uses Rune Chains or Skull-Chain twice. She can instead replace both uses of Rune Chains or Skull-Chain with two more melee attacks.

Multiattack (Shackled Only). Andariel casts Rune Chains once, then makes three ranged attacks.

Clawed Hand (Fiend Form Only). Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 7) slashing damage plus 13 (2d12) poison damage.

Backlimb (Unshackled Only, Fiend Form Only). Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 16 (2d8 + 7) piercing damage plus 19 (3d12) poison damage.

Dragging Chains. Melee Weapon Attack: +13 to hit, reach 20 ft., one target. Hit: 20 (3d8 + 7) Slashing or Bludgeoning damage (Andariel's choice), and the target must succeed on a DC 20 Strength saving throw or have their speed halved for 1 minute.

Skull-Chain (Unshackled Only). Melee Weapon Attack: +13 to hit, reach 25 ft., one target. Hit: 16 (2d8 + 7) Slashing or Bludgeoning damage (Andariel's choice) plus 13 (3d8) Fire damage. The chains leave a 5-foot wide, 15-foot long tear of hellish energy across the ground that remains until the end of Andariel's next turn. Whenever a target enters the area of the tear, they must make a DC 19 Dexterity, Constitution, or Charisma saving throw (target's choice), taking 10 (3d6) fire damage on a failed save, or half as much on a success.

Flamebolt. Melee Weapon Attack: +15 to hit, range 40/140 ft., one target. Hit: 18 (2d10 + 9) Fire or Necrotic damage (Andariel's choice).

Rune Chains. Andariel summons a Medium-sized statue of a feminine figure wrapped in glowing red chains at a point she can see within 120 feet of her. The statue generates an aura around it in a 15-foot radius, and remains for 1 minute until destroyed (it has AC 16, 50 hit points, and resistance to fire, cold, nonmagical bludge/slash/pierce damage, and immunity to poison damage). Any target that enters the area of the statue must succeed on a DC 20 Wisdom saving throw or have its speed halved and have disadvantage on attack rolls against targets other than the statue, as hellish chains restrain it from moving too far.

Teleport. Andariel magically teleports, along with any equipment she is wearing or carrying, up to 120 feet to an unoccupied space she can see.

Chain Sweep (Unshackled Only). Andariel sweeps one of her flaming chains in an arc in front of her. Each target within 15 feet of her that is in front of her must make a DC 19 Dexterity saving throw, taking 16 (2d8 + 7) Bludgeoning damage + 13 (2d12) Fire damage on a failed save, or half as much on a success. If the target succeeds on the saving throw by 2 or more, Andariel takes 7 (2d6) Fire damage from backlash of not being able to control her own power.

Fist Slam (Unshackled Only). Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 23 (3d10 + 7) bludgeoning damage plus 9 (2d8) poison damage, and any target within 15 feet of the target, along with the target itself, must make a DC 20 Strength saving throw, taking 9 (2d8) bludgeoning damage and be knocked prone on a failed save, or half as much damage and no other effects on a success.

Summon Fiend (4/Short or Long Rest). Andariel performs a magical summoning to summon 2d4+1 demoliths or demons of CR 7 or lower. 

A summoned fiend appears in an unoccupied space within 60 feet of its summoner, acts as an ally of its summoner, and can’t summon other fiends. It remains for 1 minute, until it or its summoner dies, or until its summoner dismisses it as an action.

Flame Cross (Recharge 4-6). Andariel releases a quick burst of energy before causing three 5-foot wide, 45-foot long lines of dark fire to burst from the area where she is standing in different directions. Each target in any of those areas when the flames burst forth must make a DC 20 Dexterity saving throw, taking 39 (6d12) fire damage + 7 (2d6) poison damage and being knocked prone on a failed save, or half as much on a success.

Arena of Anguish (Recharge 4-6, Fiend Form Only). Andariel floats up into the air around a dust cloud she creates before causing numerous rippling bolts of flame to travel through the area, moving slowly but tracking down anything they can touch. For the next 1 minute, every time a target starts its turn within the non-dusty area of the dust cloud, it must make a DC 19 Dexterity saving throw, taking 23 (4d6 + 9) fire damage + 9 (2d8) poison damage on a failed save, or quarter as much on a success.

Flame Wave (Recharge 4-6). Andariel causes hellish flames to burst forth from the ground around her in the shape of a 30-foot cone. Each target within the area of the flames must make a DC 18 Dexterity saving throw, taking 33 (6d10) fire damage + 10 (3d6) poison damage on a failed save, or half as much damage on a success.

Draining Kiss (Fiend Form Only). Andariel kisses a creature charmed by her or a willing creature. If the target is not willing, Andariel may attempt a grapple (+5 to hit, automatic Grappled on a hit). The target must make a DC 21 Constitution saving throw against this magic, taking 40 (7d8 + 9) psychic damage on a failed save, or half as much damage on a successful one. The target's hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.

Innate Spellcasting. Andariel's spellcasting ability is Charisma (Spell save DC 25, +16 to hit with spell attacks). Andariel innately casts one of the following spells, requiring no material components:

At will: Animal Messenger, Cause Fear, Earth Tremor, Ray of Sickness (4th level version), Confound Senses, Gaseous Form

2/day each: Dominate Person, [Tooltip Not Found],  Fiendish Brand, Danse Macabre

3/day: Mind Blank, Teleport, Feeblemind

Swift Agony (Recharge 6). Andariel charges herself up in order to strike down her foes in the fastest and most painful way possible. For the next 1 minute, all of Andariel's attacks have a +4 bonus to hit, and her speeds increase by 10 feet each. Additionally, on each of her turns, as a bonus action, she can move up to half her speed.

Andariel 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. Andariel regains spent legendary actions at the start of its turn.

Smack. Andariel makes a melee attack. If the attack hits, she can choose to deal half as much damage in exchange for knocking the target backward 10 feet.

Rune Chains. Andariel uses her Rune Chains.

Inferno Attack (Costs 2 Actions). Andariel uses her Flame Cross or Flame Wave. If she has to roll to recharge, she has advantage on the roll.