Legendary Resistance (3/day). If Xy’orthul fails a saving throw, it can choose to succeed instead.

Spellcasting. Xy'orthul's is a 20th level spellcaster. It’s spellcasting ability is Charisma (spell save DC 28). It can innately cast the following spells requiring no material components:

At will: eldritch blast, scatter, feeble mind, teleport

3/day each: mind blank, teleportation circle

1/day each: gate, time stop

Divine Presence. Any creature hostile to Xy'orthul that starts its turn within 240 feet of it must succeed on a DC 28 Wisdom saving throw or be frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, 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 Xy'orthul's Divine Presence for the next 24 hours.

Maddening Aura.  Any creature that starts its turn within 60 feet of Xy'orthul must succeed on a DC 28 Intelligence saving throw or take 55 (10d10) psychic damage and become permanently insane. An insane creature behaves erratically, as determined by the DM.

Dreamwalker. Xy'orthul can traverse the Far Realm at will, and it can invade the dreams of any creature it chooses, regardless of plane or distance.

Presence of the Far Realm. Xy'orthul's presence warps reality within a 5-mile radius. Time and space become unpredictable, causing the environment to shift and twist. This effect can alter the terrain, create or destroy structures, and even manipulate the flow of time at the deity's whim.

Omnipotent Mind. Xy'orthul has complete control over the minds of all creatures within its vicinity, allowing it to manipulate their thoughts, perceptions, and actions as it sees fit.

Tentacle Grasp. Melee Weapon Attack: +20 to hit, reach 30 ft., one target. Hit: 40 (8d8 + 10) bludgeoning damage and the target is grappled (escape DC 28). Until this grapple ends, the target is restrained and Xy'orthul can't use this tentacle on another target.

Eldritch Maelstrom (Recharge 6). Xy'orthul summons a swirling vortex of eldritch energy in a 100-foot radius centered on itself. Each creature in that area must make a DC 28 Wisdom saving throw, taking 90 (20d8) psychic damage and becoming stunned for 1 minute on a failed save, or half as much damage and not stunned on a successful one. A stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Xy'orthul, The Dreaming Void can take 3 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. Xy’orthul regains spent legendary actions at the start of its turn.

Tentacle grasp. Xy'orthul makes one tentacle grasp attack.

Eldritch Blast (Costs 2 Actions). Xy'orthul casts eldritch blast.

Scatter (Costs 3 Actions). Xy’orthul casts scatter.

Teleport (Costs 3 Actions). Xy'orthul casts teleport to teleport itself up to 120 feet to an unoccupied space it can see.