Ungodly Master

Legendary Resistance (5/Day) If the Ungodly Master fails a saving throw they can choose to succeed instead.

Aberrant Regeneration If the Ungodly Master has at least 1 HP left they regain 30 HP at the start of each round.

Arcane Deviant  Ungodly Master cannot be affected by spells of 6th level or lower unless they wish to be

Telepathy   Ungodly Master can speak into the minds of all creatures within 120 feet.

Magic Attacks Ungodly Master's attacks are magical.

Psychic Shield  Whenever the Ungodly Master takes damage from 10 feet away or closer, the attacker takes 5d6 psychic damage

Spellcasting. The Ungodly Master is a 24th-level spellcaster. Its spellcasting ability is CHA (spell save DC 26, +13 to hit with spell attacks). The Ungodly Master has following Warlock spells prepared:
Cantrips : chill touch, scorching ray, friends 
1st level 6 slots: disguise self, charm person, bane, cause fear, hex, inflict wounds

2nd level 4 slots: crown of madness, alter self darkness, mind spike, blink

3rd level 4 slots: bestow curse, counterspell, feign death, fly

4th level 4 slots: blight, confusion, shadow of moil, hallucinatory terrain

5th level 3 slots: contagion, dominate person, synaptic static

6th level 2 slots: mental prison, harm

7th level 2 slots: power word pain, reverse gravity

8th level 1 slot: maddening darkness, demiplane

9th level 1 slot: time stop

Multiattack.  Ungodly Master attempts to psychicly intrude, then makes 3 Necrotic Blade attacks and 2 Otherworldly Arrows attacks.

Necrotic Blade. Melee Weapon Attack: +17 to hit, reach 15 ft., 1 target. Hit:   (5d12 + 17) necrotic damage. 

Otherworldly Arrows. RangedWeapon Attack: +17 to hit, range 300/750 ft., 3 target. Hit: 78 (5d10  +17 ) force damage.

Summon Aberration  Ungodly Master summons a star spawn mangler, a chuul, or two intellect devourers in an unoccupied space they can see within 30 ft of them. The Aberration follow the Ungodly Master's commands in spirit as well as the letter. Up to three creatures or two creatures and two intellect devourers can be alive at one time.All creature summoned by The Ungodly Master disintegrate upon the Ungodly Masters death.

Psychic Intrusion     Ungodly Master attempts to glean information from an enemy's mind. Ungodly Master forces a target to make a DC 26 Intelligence saving throw or the Ungodly Master penetrates their mind, reading their surface thoughts. Ungodly Master has advantage on attack rolls and saving throws from effects against the target, and the target has disadvantage on all attack rolls against Ungodly master for 3 rounds.

Control Dominated Person    Ungodly Master commands the dominated creature to do an action they are capable and does not directly harm themselves.

Reality Ripple    As long as they are on their home plane Ungodly Master can cause space around them to distort and ripple, forcing creatures within a 60 ft sphere to make a constitution saving throw or take 8d8 bludgeoning damage and be knocked prone on a failed save or half as much damage and they are not knocked prone.

Summon Aberration  Ungodly Master summons a star spawn mangler, a chuul, or two intellect devourers to an unoccupied space they can see within 30 ft of them. The Aberration follow the Ungodly Master's commands in spirit as well as the letter.Up to three creatures or two creatures and two intellect devourers can be alive at one time. All creature summoned by The Ungodly Master disintegrate upon the Ungodly Masters death.

Necrotic Blade   Ungodly Master makes a necrotic blade attack.

Spell.  Ungodly Master casts a spell of 3rd level or lower, that costs 1-3 actions in accordance with the spell level. (1st level- 1 action, 2nd level- 2 actions, etc.)

Psychic Intrusion     Ungodly Master attempts to glean information from an enemy's mind. Ungodly Master forces a target to make a DC 26 Intelligence saving throw or the Ungodly Master penetrates their mind, dealing 5d8  psychic damage and reading their surface thoughts. Ungodly Master has advantage on attack rolls and saving throws from effects against the target, and the target has disadvantage on all attack rolls against Ungodly master for 3 rounds.

Occultic possession  (Costs 3 Action) The Ungodly Master targets 3 creature it can see within 30 ft and attempts to dominate them. The target must succeed on a DC 27 wisdom saving throw or be charmed for 1 minute or until a successful save. The target obeys all commands that are not directly hurtful to it. Ungodly Master issues all commands as a bonus action. The target makes a save on the start of each of its turn