Chichimec

Immutable Form. The Chichimec is immune to any spell or ability that would alter its form.

Regeneration. The Chichimec heals 10 hit points at the beginning of its turn.

Innate Spellcasting. The Chichimec can cast these following spells at-will or multiple times a day, using its Charisma ability score. (DC 21, +13 to hit)

At-will: darkness, telekinesis

3/day: control weather, lightning bolt, call lightning

1/day: chain lightning, storm of vengeance

Action Name. The Chicimec makes three wing buffet attacks and then makes a tail slam attack.

Wing Buffet. Melee Weapon Attack: +# to hit, reach 5 ft., one target. Hit:  19 (3d6 + 9) bludgeoning damage. 

Tail Smash. Melee Weapon Attack: +# to hit, reach 15 ft., one target. Hit: # (4d8 + ) bludgeoning damage plus 1d3 Charisma drain. A creature can negate the Charisma drain on a DC 21 Charisma saving throw. The Chichimec gains 16 (3d10) temporary hitpoints after successfully draining Charisma. When a creature's Charisma is reduced to 0, they die instantly and the Chichimec regains 50 hit points.

Summon Air Elemental (3/day). The Chichimec summons an Air Elemental which appears within 15 ft. of it. The Air Elemental obeys every command of the Chichimec, and is allied to it. The summoned elemental remains until it is killed or until 10 minutes have elapsed.

Enter the description for how legendary actions work for your monster here.

Fly. The Chichimec flies up to its speed.

Wing Buffet. The Chichimec makes a Wing Buffet attack against an enemy within range.

Tail Smash (Costs 2 Actions). The Chichimec makes a Tail Smash attack against an enemy within range.

Summon Air Elemental (Costs 3 Actions). The Chichimec uses its Summon Air Elemental action, provided it still has charges for it.