Ahrumon Snowmark the Harbinger of Death

Pervasive Evil. Each round after he takes a wound the wound fills with another eye and increases his attack power by either damage or number of attacks in alternating fashion. 

Spellcasting. Ahrumon is a 9th-level spellcaster. Its spellcasting ability is Wisdom (spell save DC 22, +12 to hit with spell attacks). Ahrumon has following Wizard spells prepared:

1st level (4 slots): Absorb Elements, Shield

7th level (1 slot): Project Image

9th level (1 slot): Invulnerability

Claws. Melee Weapon Attack: +12 to hit, reach 20 ft., 1 target. Hit: 33 (4d12 + 10) slashing damage. On a successful melee attack the target is grappled and is considered restrained. While restrained in this way the eyes in the palms of his hands drain life force from the entity at a rate of 4d10 or half if the target succeed a CON save of 20. 

Eye Rays. RangedWeapon, range 160 ft.

1. Disintegration Ray. If the target is a creature, it must succeed on a DC 21 Dexterity Saving throw or take 50 (10d10) force damage. If this damage reduces the creature to 0 hit points, its body becomes a pile of fine gray dust.
2. Death Ray. The targeted creature must succeed on a DC 21 Dex saving throw or take 60 (10d12) necrotic damage. the target dies if the ray reduces it to 0 hit points.
3. Slowing Ray. The targeted creature must succeed on a DC 21 Dex Saving throw. On a failed save, the target's sped is halved for 1 minute. In addition, the creature can't take reactions, and it can take either an action or a bonus action, 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.
4. Paralyzing Ray. The targeted creature must succeed on a DC 21 Constitution save 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.
5. Telekinetic Ray. If the target is a creature, it must succeed on a DC 21 strength saving throw or the beholder moves it up to 30 feet in any direction. It is restrained by the ray's telekinetic grip until the start of Ahrumon's next turn or until he is incapacitated.
6. All seeing eye Ray. The targeted creature must make a DC 21 Wisdom saving throw. On a failed save, the creature can no longer hide from Ahrumon and his eye will always know where the creature is. The creature cannot gain advantage on an attack through flanking if they are affected by this ray. They can make the save at the end of each of its turns, ending the effect on itself on a success.
7. Gravity Ray. Each target in a 160 ft cone must make a DC 21 strength saving throw. On a failed save, the target is pulled or pushed 30 feet towards Ahrumon whatever he chooses. This effect lasts for 1 minute and continues to pull or push based on Ahrumon's initial choice until the duration ends. They can make the save at the end of each of its turns, ending the effect on itself on a success.
8. Blood Bullet Ray. The eye that discharges this destroys itself and emits a pool of floating blood that hardens and crystallizes before rushing towards its target. Each target in a 160 foot cone must make a DC 21 Dexterity Saving throw or be pierced by these blood bullets. On a failed save, the target takes 12d10 piercing damage and half of that on a successful save. 

Blood Revenge. If the creature takes physical damage that would draw blood on a turn he can use his reaction to crystallize the blood and discharge it at his attacker dealing 4d10 damage.

Ahrumon can take 3 legendary actions, using his rays each turn. It can only use one at a time and it can occur only after another creature has gone. He regains his used actions at the start of his next turn.

Eye Ray (Costs 1 Actions). Ahrumon uses one of his rays at random (roll 1d8 to determine).