The Forgotten God

Legendary Resistance (6/Day). If the Forgotten God fails a saving throw, it can choose to succeed instead.

Limited Magic Immunity. Unless it wishes to be affected, the Forgotten God is immune to spells of 6th level or lower. it has advantage on saving throws against all other spells and magical effects.

Magic Weapons. The Forgotten Gods weapon attacks are magical.

Regeneration. The Forgotten God regains 50 hit points at the start of its turn.

Discorporation. When the Forgotten God is dropped to 0 hit points or dies, its form dies but its essence is re-sealed to the Realm it was forgotten in. It is unable to be re-summoned to this plane until a new chosen warlock performs its ritual.

Corrupting Aura. Creatures that are within 100ft of The Forgotten God must be protected by either high tier (8th or higher) magic or have a Gods protection to be able to approach The Forgotten God without being Corrupted by its aura. Non protected creatures that displease the Forgotten God take 12d12 Necrotic damage each minute.

Siege Destroyer. The Forgotten God deals triple damage to structures and objects.

Multiattack. The Forgotten God can use its frightful presence. it then makes 6 attacks: 3 Dark Tendrils, 1 Corrupting Spray, 1 Paralyzing Touch and 1 Mind Melt.

Dark Tendrils. Melee Weapon Attack: +20 to hit, reach 20 ft., one target. Hit: 36 (6d8 + 12) Piercing damage. 

Corrupting Spray. RangedWeapon Attack: +20 to hit, range 30 ft cone. Hit: 27 (5d6 + 12) Necrotic damage. Creatures must make a DC 18 wisdom saving throw if hit, becoming Frightened on a failure.

Paralyzing Touch. Melee Weapon Attack: +20 to hit, reach 20 ft., one target. If hit by Paralyzing Touch the creature must make a DC 20 constitution saving throw, becoming paralyzed until The Forgotten Gods next turn on a failure.

Mind Melt. RangedWeapon Attack: +20 to hit, Range 50ft., one target. Hit: 42 (10d6 + 12) Psychic damage. If hit by this attack the creatures Intelligence and wisdom score is lowered by 1 until the end of its next turn.

Frightful Presence. Each creature of the Forgotten Gods choice within 120 feet of it and aware of it must succeed on a DC 18 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, with disadvantage if the Forgotten God is within line of sight, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the Forgotten Gods Frightful Presence for the next 12 hours.

Fearful Blow. If a creature is Frightened and attacks The Forgotten God, as a reaction the Forgotten God can use a Dark Tendril attack on that creature.

The Forgotten God can take 4 legendary actions, choosing from the options below. Only one legendary action option can be used at a time, and only at the end of another creature’s turn. The Forgotten God regains spent legendary actions at the start of its turn.

Dual Tendrils (Costs 1 Action). The Forgotten God makes a double Dark Tendril attack on a single target.

Enthrall (Costs 2 Actions). A creature of the Gods choosing must make a DC 16 Intelligence Saving throw, the creature is charmed until the start of the Forgotten Gods turn. Creatures with lower than a 5 intelligence automatically fail. 

Recover (Costs 2 Actions). The Forgotten God focuses upon regenerating itself, unless it has taken radiant damage in this round, the Forgotten God will regenerate 12 (2d12) hit points.

The Forgotten Realm (Costs 4 Actions). The Forgotten God opens a portal within 10 ft to the realm of his isolation, the unspeakable horrors that have been created by The Forgotten God strike out from within. All creatures within 10 ft of the portal must make a DC 28 Dexterity saving throw, taking 82 (7d20 + 12) Necrotic plus 6 (2d6) Cold Damage on a failure, half as much damage on a success.

Judgement Day (Costs 4 Actions). The Forgotten Gods arrival on the material plane is a sign of the end times for all creatures. By calling on his full power he blasts a creature with dark energies, twisting there bodies and mind. The Forgotten God chooses one creature within 10 ft of it to call judgement upon, that creature must make a DC 28 Constitution saving throw, Taking 162 (15D20 +12) Necrotic damage on a failed save, or half as much damage on a success. Targets killed by this attack cannot be revived by any means other than a greater deity.