Elder Arcanaloth

 Elder Arcanaloth mediun fiend (yugoloth), neutral evil

Armor Class 19 (natural armor)

Hit Points 130 (20d8+40)

Speed 40 ft., fly 60 ft.

STR 17 (+3)

DEX 14 (+2)

CON 14 (+2)

INT 24 (+7)

WIS 16 (+3)

CHA 17 (+3)

Saving Throws Dex +7, Int +12, Wis +8, Cha +8

Skills Arcana +17, Deception +13, Insight +13, Perception +13

Damage Resistances cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical attacks

Damage Immunities acid, poison

Condition Immunities charmed, poisoned, frightened

Senses truesight 120 ft., passive Perception 23

Languages all, telepathy 120 ft.

Proficiency Bonus +5

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

Magic Weapons. The arcanaloth's weapon attacks are magical.

Legendary Resistance (2/day). When the arcanaloth fails a saving throw it can choose to succeed instead.

Eldritch Focus. The elder arcanaloth can concentrate on two spells at the same time. It must make only one concentration save to maintain concentration on both spells.

Actions

• Claws. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) slashing damage. The target must make a DC 15 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful one.
• Teleport. The arcanaloth magically teleports, along with any equipment it is wearing or carrying, up to 90 feet to an unoccupied space it can see.
• Spellcasting. The arcanaloth is a 20th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 20, +12 to hit with spell attacks). The arcanaloth can cast the following spells:
• At will: mage hand, detect magic, magic missile, alter self, darkness
• 5/day each: mirror image, hold monster, fireball, counterspell
• 3/day each: chain lightning, finger of death, plane shift
• 1/day each: foresight, dominate monster