Balor

Demonic Flames. Creatures resistant to fire damage aren't resistant to fire damage dealt by the balor. Creatures immune to fire damage are still immune to the balor's fire damage.

Demonic Resilience. The balor is resistant to cold and lightning damage. In addition, it is immune to poison damage and to the poisoned condition.

Diving Assault. If the balor is flying and moves at least 30 feet straight toward a creature and then hits it with a Gore attack on the same turn, that target must succeed on a DC 20 STR save or be knocked prone. If the target is prone, the balor can make one Longsword attack against it as a bonus action.

Flaming Weapons. The balor's weapon attacks are magical. When the balor hits with any weapon, the weapon deals an extra 3d8 fire damage (included in the attack).

Fire Aura. At the start of each of the balor's turns, each creature within 10 feet of it takes 13 (3d8) fire damage, and flammable objects in the aura that aren't being worn or carried ignite.

Magic Resistance. The balor has advantage on saves against spells and other magical effects.

Multiattack. The balor makes one Gore attack, one Longsword attack, and one Whip attack.

Gore. _Melee Weapon Attack:_ +14 to hit, reach 10 ft., one target. _Hit:_ 15 (2d6+8) piercing damage plus 13 (3d8) fire damage.

Longsword. _Melee Weapon Attack:_ +14 to hit, reach 10 ft., one target. _Hit:_ 21 (3d8+8) slashing damage, or 24 (3d10+8) slashing damage if used with two hands, plus 13 (3d8) fire damage. If the balor scores a critical hit, it rolls damage dice three times, instead of twice.

Whip. _Melee Weapon Attack:_ +14 to hit, reach 30 ft., one target. _Hit:_ 15 (3d4+8) slashing damage plus 13 (3d8) fire damage, and the target must succeed on a DC 20 Strength saving throw or be pulled up to 25 feet toward the balor.

Teleport. The balor magically teleports, along with any equipment it is wearing or carrying, up to 60 feet to an unoccupied space it can see.