Epic Boss Hit Points. Increase Epic Alyxian Aboleth's starting hit points and hit dice by 60(5d10 + 60) for each player character above four, or reduce its starting hit points and hit dice by that amount for each player character below four.

Amphibious. The aboleth can breathe air and water.

Mucous Cloud. While underwater, the aboleth is surrounded by a cloud of sticky mucus. A creature that touches the aboleth or hits it with a melee attack while within 5 feet of it must succeed on a DC 14 Strength saving throw or be restrained until the end of the aboleth’s next turn.

Probing Telepathy. If a creature the aboleth can see communicates telepathically with the aboleth, the aboleth learns the creature’s greatest desires.

The aboleth always takes its turn on Initiative count 20. On its turn, the aboleth can use its movement and interaction as normal. However, it does not take an action or Bonus Action on its turn unless forced to do so by a spell or other effect. Instead, the aboleth takes one of the following Epic Actions at the end of each player character's turn:

Tentacle. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 12 (2d6 + 5) bludgeoning damage plus 3 (1d6) psychic damage.

Tail (1/round). Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage, and the target is pushed up to 15 ft in any direction.

Bite (1/round). Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) piercing damage. The target is Bleeding 2d6: they lose 7 (2d6) HP at the end of each of their turns until they regain hit points or someone uses a medicine kit charge on them as an action.

The Aboleth can pull a creature it has Grappled into reach to make this attack against it.

Consume Memories (1/round). Intelligence Saving Throw: DC 16, one creature within 30 feet that is Charmed or Grappled by the aboleth. Failure: 21 (6d6) Psychic damage. Success: Half damage. Failure or Success: The aboleth regains hit points equal to the damage dealt. It also gains the target’s memories if the target is reduced to 0 Hit Points by this action.

Call of the Deep (1/round). If the Aboleth has no spawn in combat with it, it summons an Aboleth Spawn from the depths to aid it.

Dash (1/round). The aboleth moves up to its speed.

Epic Resistance. The aboleth chooses one condition, spell, or other effect currently affecting them and rolls 1d20. On an 11+, the effect ends on it. The aboleth can use this action even if it would otherwise be unable to take actions, its actions are being controlled by another creature, or if a spell or effect alters its game statistics.

Deep Domination (Recharge 4–6). The aboleth targets one creature it can see within 30 feet of itself. The target must succeed on a DC 17 Wisdom saving throw or be magically charmed by the aboleth until the aboleth dies or until it is on a different plane of existence from the target. The charmed target is under the aboleth’s control and can’t take reactions, and the aboleth and the target can communicate telepathically with each other over any distance.

The charmed target can repeat the saving throw whenever it takes damage, ending the effect on itself on a success. No more than once every 24 hours, the target can repeat the saving throw when it is at least 1 mile away from the aboleth.

Sacrificial Pawn. Trigger: The aboleth takes damage from an attack. Response: The aboleth chooses an ally (or a creature Charmed by it) within 30 ft to take the damage instead.