Balor

Huge Fiend (Demon), Chaotic Evil

AC 19     Initiative +14 (24)
HP 287 (23d12 + 138)
Speed 40 ft., Fly 80 ft.

Ability Scores
STR 26 (+8) Save +8    DEX 15 (+2) Save +2    CON 22 (+6) Save +12
INT 20 (+5) Save +5    WIS 16 (+3) Save +9    CHA 22 (+6) Save +6

Skills Perception +9
Resistances Cold, Lightning
Immunities Fire, Poison; Charmed, Frightened, Poisoned
Senses Truesight 120 ft.; Passive Perception 19
Languages Abyssal; telepathy 120 ft.
CR 19 (XP 22,000; PB +6)

Traits
Death Throes. When the balor dies, it explodes. Each creature in a 30-foot emanation must make a DC 20 Dexterity saving throw, taking 31 (9d6) fire damage and 31 (9d6) force damage on a failed save, or half as much on a successful one. If the balor dies outside the Abyss, it instantly reforms there with full HP.
Fire Aura. At the end of each of the balor’s turns, each creature in a 5-foot emanation takes 13 (3d8) fire damage.
Legendary Resistance (3/Day). If the balor fails a saving throw, it can choose to succeed instead.
Magic Resistance. The balor has advantage on saving throws against spells and magical effects.

Actions
Multiattack. The balor makes one Flame Whip attack and one Lightning Blade attack.
Flame Whip. Melee Attack: +14, reach 30 ft. Hit: 18 (3d6 + 8) force damage plus 17 (5d6) fire damage. The target, if Huge or smaller, is pulled up to 25 feet toward the balor and is knocked prone.
Lightning Blade. Melee Attack: +14, reach 10 ft. Hit: 21 (3d8 + 8) force damage plus 22 (4d10) lightning damage. The target cannot take reactions until the start of the balor’s next turn.

Bonus Actions
Teleport. The balor teleports itself or a willing demon within 10 feet up to 60 feet to an unoccupied space it can see.