Aeorian Devastator

Antimagic Cone. The Devastator reveals an eye on is chest that creates an area of antimagic, as in the antimagic field spell, in a 75-foot cone.  At the start of each of its turns, the Devastator decides which way the cone faces and whether the cone is active.  The area works against the Devastator's own magic.

Absorption. All spells cast against the Devastator are either resisted or completely absorbed (when radiant or necrotic damage).  Half of the attack damage is converted to reserved damage.  The other half is deducted from the Devastator's hit points. When the Devastator absorbs more than 15 points of spell damage, it starts to float just above the ground. The Devastator can absorb up to its current hit points + 30.

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

Regeneration. The Devastator regains 10 hit points at the start of its turn if it has at least 1 hit point.

Multiattack. The Devastator makes three attacks, one with its eye rays and two with its claws.

Claws. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 10 (1d10 + 5) slashing damage.

Eye Rays. The devastator shoots three of the following magical eye rays at random (roll 3d8, reroll duplicates), choosing one to three targets it can see within 75 feet of it:

   1.  Return Ray. The Devastator targets a creature, and returns one type of damage received on prior turns. Damage is 2d10 + up to 10 additional damage.  (Deduct from stored damage points.)  Targeted creature must succeed on a DC 16 Dexterity saving throw. On a successful save, the creature takes half the dice damage + the additional damage.
   2.    Paralyzing Ray. The targeted creature must succeed on a DC 16 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
    3. Fear Ray. The targeted creature must succeed on a DC 16 Wisdom saving throw or be frightened for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
    4. Slowing Ray. The targeted creature must succeed on a DC 16 Dexterity saving throw. On a failed save, the target’s speed is halved for 1 minute. In addition, the creature can’t take reactions, and it can take either an action or a bonus action on its turn, not both. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
    5. Enervation Ray. The targeted creature must make a DC 16 Constitution saving throw, taking 18 (4d8) necrotic damage on a failed save, or half as much damage on a successful one. The Devastator can add up to 10 points of reserved damage to this attack, which is not halved on a save.
    6. Petrification Ray. The targeted creature must make a DC 16 Dexterity saving throw. On a failed save, the creature begins to turn to stone and is restrained. It must repeat the saving throw at the end of its next turn. On a success, the effect ends. On a failure, the creature is petrified until freed by the greater restoration spell or other magic.
    7. Disintegration Ray. If the target is a creature, it must succeed on a DC 16 Dexterity saving throw or take 36 (8d8) force damage. If this damage reduces the creature to 0 hit points, its body becomes a pile of fine gray dust. If the target is a Large or smaller non-magical object or creation of magical force, it is disintegrated without a saving throw. If the target is a Huge or larger object or creation of magical force, this ray disintegrates a 10-foot cube of it. The Devastator can add up to 10 points of reserved damage to this attack, which is not halved on a save.
    8. Death Ray. The targeted creature must succeed on a DC 16 Dexterity saving throw or take 45 (8d10) necrotic damage. The target dies if the ray reduces it to 0 hit points.

Eyes of Nine. The Devastator absorbs magical damage against it, and can return or redirect half of the damage dealt as a reaction. The remaining absorbed damage is added to the reserved damage and can be dealt on other eye ray attacks.

The Devastator can take one legendary action, using an Eye Ray.  It can only take one legendary action per round. and only at the end of another creature's turn.  The Devastator regains spent legendary actions at the start of its turn.