Arnessia of the beyond

Fear Aura: Any creature Hostile to Arnessia that starts its turn within 20 feet of Arnessia must make a DC 22 Wisdom saving throw. On a failed save, the creature is Frightend until the start of its next turn. If a creature's saving throw is successful, the creature is immune to  Arnessia's Fear Aura for the next 24 hours.

Magic resistance: Arnessia has advantage on saving throws against spells and other magical effects.

Magic weapons: Arnessia's weapon attacks are magical.

Innate spellcasting: Arnessis spellcating modifier is Charisma (spell save DC 21). Arnessia can innately cast the following spells, requiring no material components:
At will: Detect magic, Fireball, Dispel evil and good 
3/day each: Hold monster, Wall of fire

Strange ways: when a creature is forced to make a saving throw by Arnessia. Where the creature would take half damage on a success and full damage on fails. They instead take half damage on a failure and full damage on a success. She can also choose to take a legendary action at the begging or end of all turns (included in Legendary actions chart).

Multiattack: Arnessia makes five attacks: one with her bite, one with her claw, two with Catchalasia , and one with her tail.

Teleport: Arnessia teleport's up to 100 ft to an unoccupied area.  

Bite: Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 22 (4d6 + 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 34 (6d8) 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.

Catchalasia: Melee weapon Attack:  +15 to hit, reach 10 ft., one target. Hit 27 (5d10+9) bludgeoning damage. Plus the creature must succeed on a DC 20 constitution saving throw or take 12 (3d6) fire damage on a failed save and have as much on a success 

Claw: Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 17 (2d8 + 9) slashing damage..

Tail: Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 24 (3d10 + 9) bludgeoning damage.

Arnessia can make three Legendary actions, Choosing from the list below. She can use them only at the begging or end of anyone's turn (including hers). Arnessia regains all spent charges at the end of her next turn.

Attack. Arnessia makes one claw attack.

Time warp (Costs 2 Actions). Arnessia slows down time to a complete stop for one minute. She is enabled to walk up to half her walking speed, make one bite attack, and/or fly's up to half her flying speed, during this time. Once over. Time goes on as normal, and no one realizes what happen'd unless they looked back in time.

Summon spectral (Costs 2 Actions).  Arnessia summons 2 shadows. See monster Manuel  for information about shadows.