Cacodaemon

Infernal Presence. The cacodemon emanates an aura of fear and malevolence, causing creatures within 30 feet of it to have disadvantage on Wisdom saving throws against being frightened.  Additionally, as a bonus action, the cacodemon can unleash a terrifying roar. Each creature of its choice within 30 feet of the cacodemon that can hear it must succeed on a DC 15 Wisdom saving throw or become frightened for 1 minute. A frightened creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. When the fear effect ends on the creature, they cannot be frightened by the cacodemon again for 24hrs. 

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

Multiattack. The cacodemon makes three attacks. 

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 26 (3d10 + 4) piercing damage.

Claw. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 22 (3d8 + 4) slashing damage, plus 10 (2d6+4) acid damage.

Spit from The Pit. Ranged Spell Attack: +7 to hit, range 60/240ft, one target. Hit: 24 (4d10) acid damage. 

Fiery Gaze (Recharge 5-6). The cacodemon targets a 20ft radius it can see within 60 feet of it. The targets must make a DC 16 Dexterity saving throw, taking 42 (10d6) fire damage on a failed save, or half as much damage on a successful one.

Summon Demon (1/day). The cacodemon attempts to summon 1d4 dretches, or another cacodemon (with a 50% chance of success). A summoned demon appears in an unoccupied space within 60 feet of its summoner, acts as an ally of its summoner, and can't summon other demons. It remains for 1 minute, until it or its summoner dies, or until its summoner dismisses it as an action.

Winged Charge. The cacodemon flies up to its speed in a straight line. During this movement, it can make a bite attack against a creature it flies over. If the attack hits, the target must succeed on a DC 15 Strength saving throw or be knocked prone.

Opportunity Attack: The cacodemon can make a claw attack at a creature leaving its reach.

The cacodemon 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. The cacodemon regains spent legendary actions at the start of its turn.

Claw Attack. The cacodemon makes one claw attack.

Fiery Gaze (Costs 2 Actions). The cacodemon uses its Fiery Gaze.

Teleport. The cacodemon magically teleports up to 60 feet to an unoccupied space it can see.