Armageddon

Eyeless. Armageddon is blind and perceives the world through sound; as long as it cannot hear a creature, that creature cannot be seen by Armageddon. If Armageddon is Deafened, it is also Blinded.

Crazed Dash. As long as Armageddon cannot see a creature, its movement speed is doubled.

Feast. When Armageddon consumes a creature with Chow Down it gains the following depending on the ability scores of the creature it ate. It will only gain one, depending on what the highest ability score of the creature was.

1. Strength > 15: +1 damage die to all attacks.
2. Dexterity > 15: +2 to armor class and +5 ft. to movement speed.
3. Constitution > 16: Regain a number of HP equal to that creature's amount of remaining hit die.
4. Intelligence > 15: Advantage on a saving throws using Charisma, Wisdom, or Intelligence.
5. Wisdom > 18: Ignore the Eyeless Special trait.
6. Charisma > 10: Armageddon can now speak by mimicking the voice of the creature it just ate. 

Multiattack. Armageddon can attack twice each turn as long as its first attack is Maws of Life.

Maws of Life. Melee Unarmed Attack: +8 to hit, reach 15 ft., 1 target. Hit: 32 (6d8 + 5) Piercing damage. If the target of this attack is hit, it must succeed on a DC 18 Strength saving throw or be Grappled by Armageddon.

Vile Spit. RangedUnarmed Attack: +8 to hit, range 20/35 ft., 1 target. Hit: 23 (5d8) Acid damage. If Armageddon is attacking a creature within 5 ft. of itself, this attack can target up to 3 creatures instead of 1 as long as the other targets are also within 5 ft. of Armageddon or the original target of this attack.

Chow Down. If Armageddon is Grappling a creature, each turn it can use a bonus action to attempt to consume the creature; the creature must succeed on a DC 18 strength saving throw, if not, Armageddon begins swallowing that creature. If the creature fails this saving throw 3 times, it is eaten by Armageddon, gifting Armageddon new buffs depending on that creatures ability scores.

Surprised Riposte. When Armageddon is hit by a creature it cannot see, it can attempt to use Maws of Life against that creature, if this attack lands the target instantly fails the saving throw.

Armageddon can take 3 legendary actions, choosing from the options below. Only one legendary option can be used at a time and only at the end of another creature’s turn. Armageddon regains spent legendary actions at the start of its turn.

Hunger. Armageddon makes one Maws of Life attack.

Gaze into the Abyss (Costs 2 Actions). One Huge or smaller creature that Armageddon can see within 60 feet of it must succeed on a DC 18 Charisma saving throw or be frightened for 1 round and must spend its next turn going prone.

Godless Screech (Costs 3 Actions). Each creature within 60 feet of Armageddon must make a DC 18 Wisdom saving throw, taking 26 (4d10 + 4) psychic damage on a failed save, or half as much damage on a successful one.