Altraloth (Mezzoloth version)

Empowered Attacks.  The Altraloth's attacks are treated as magical for the purpose of overcoming magical resistances

Legendary Resistance (3/Day). If the Altraloth fails a saving throw, it can choose to succeed it.

Improved Critical. The Altraloth attacks score a critical on a roll of 19 or 20

Keen Hearing and Smell. The Altraloth has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Charge. If the Altraloth moves at least 20 ft. straight toward a target and then hits it with a gore attack on the same turn, the target takes an extra 9 (2d8) bludgeoning damage. If the target is a creature, it must succeed on a DC 18 Strength saving throw or be knocked prone.

Innate Spellcasting. The Altraloth's spell casting ability is Charisma (spell save DC 21). It can innately cast the following spells, requiring no material components: At will: Detect Evil And Good, Telepathy 3/day each: Move Earth, Vitriolic Sphere 1/day each: Contagion, Earthquake

Multiattack. The Altraloth makes 3 attacks. Two with its claws, and one with its horn. 

Claw. Melee Weapon Attack: +14 to hit, reach 5ft., one target. Hit: 20(2d10+8) Slashing Damage. 

Gore. Melee Weapon Attack: 14+ to hit, reach 5ft, one target. Hit: 31(3d8+8) Piercing Damage. The target must succeed on a DC 21 Constitution saving throw or become poisoned. While poisoned in this way, the target can't regain hit points, and it takes 21 (6d6) poison damage at the start of each of its turns. The poisoned target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

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

Poison Spit: As a reaction, the Altraloth can spit a ball of poison at a foe. Ranged Weapon Attack:  +8 to hit, range 30/90 feet., one target. Hit: 18 (2d8+ 8) poison damage

The Altraloth has 3 Legendary Actions, choosing from the choices below. Only one legendary action option can be used at a time and only at the end of another creature's turn. A legendary creature regains spent legendary actions at the start of its turn.

Poison Spit (Costs 1 Action). The Altraloth uses the Poison Spit reaction as an action.

Gore (Costs 2 Actions). The Altraloth uses the Gore action.

Blinding Gaze (Costs 3 Actions). The Altraloth targets one creature it can see within 30 ft. of it. If the target can see it, the target must succeed on a DC 15 Constitution saving throw or be blinded until magic such as the lesser restoration spell removes the blindness.