Ashorack

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

Devil's Sight. The ashorack can see perfectly clear in both magical and non-magical darkness with the range of its darkvision.

Magic Weapons. The ashorack's weapon, shadow spear and claw attacks are magical.

Ash cloud. As an action the ashorack can turn in to a cloud of ash and becomes incorporeal as well as able to move and be inside physical creatures and objects without problem. When it does so it gains a hover speed of 60 ft., immunity to all damage but vulnerability to radiant and psychic damage and an AC of 12. Anything the ashorack is wearing is also transformed.
(While in this form the Ashorack has unlimited HP and is immune to any effect that would alter its form.)

When it moves through a creatures space, the creature takes 17 (3d8) necrotic damage (The creature can only be affected by the necrotic damage once per round).
and must make a DC20 Wisdom savingthrow or become
frightened for 3 rounds.
If successful the creature will become immune to being frightened by this effect for 12 hours.

It returns to its physical form if it uses an action to do so or takes more than 40 damage in a single turn. When this happens it can't enter its ash cloud form for 10 minutes.
Any damage taken in its ash form does not carry over to its physical form.

Innate Spellcasting. The ashorack is an 8th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 16, +8 to hit with spell attacks). The ashorack can innately cast the following spells, requiring no material components:

At will: fire bolt, darkness, shield, mirror image, misty step

5/day: fireball, wall of force, counterspell

3/day: dimension door, forcecage, cloudkill

1/day: power word stun

Multiattack. The ashorack makes three melee attacks: two with its halberd and one with its claw. Or the ashorack makes two ranged attacks with its Shadow Spears.

Halberd. Melee Weapon Attack: +9 to hit, reach 10 ft., 1 target. Hit: 17 (2d10 + 6)  slashing damage plus 8 (1d6 + 5) fire damage.

Claw. Melee Weapon Attack: +9 to hit, reach 5 ft., 1 target. Hit: 9 (1d6 + 6) slashing damage plus 12 (2d6 + 5) psychic damage.

Shadow Spear. RangedWeapon Attack: +8 to hit, range 120/180 ft., 1 target. Hit: 15 (3d6 + 5) psychic damage. If the target is a creature, it must succeed on a DC 16 Intelligence savingthrow or become paralyzed until the Ashorack's next turn.
A successful casting of remove curse on the target will immediately end the effect.

Kick. Melee Weapon Attack: +9 to hit, reach 5 ft., 1 target. Hit: 19 (3d8 + 6)
bludgeoning damage. If the target is a creature, it must succeed on 
a DC 18 Strength savingthrow or be pushed back 30 ft. and fall prone, 
if successful the creature is only knocked back 15 ft. 
and isn't knocked prone.