Large Aberration, Lawful Evil
- AC
- 17
- Initiative
- +7 (17)
- HP
- 150 (20d10+40)
- Speed
- 10 ft., Swim 40 ft.
| Score | Mod | Save | |
|---|---|---|---|
| STR | 21 | +5 | +5 |
| DEX | 9 | -1 | +3 |
| CON | 15 | +2 | +6 |
| INT | 18 | +4 | +8 |
| WIS | 15 | +2 | +6 |
| CHA | 18 | +4 | +4 |
Traits
Amphibious. The aboleth can breathe air and water.
Eldritch Restoration. If destroyed, the aboleth gains a new body in 5d10 days, reviving with all its Hit Points in the Far Realm or another location chosen by the GM.
Legendary Resistance (3/Day, or 4/Day in Lair). If the aboleth fails a saving throw, it can choose to succeed instead.
Mucus Cloud. While underwater, the aboleth is surrounded by mucus. Constitution Saving Throw: DC 14, each creature in a 5-foot Emanation originating from the aboleth at the end of the aboleth's turn. Failure: The target is cursed. Until the curse ends, the target's skin becomes slimy, the target can breathe air and water, and it can't regain Hit Points unless it is underwater.
While the cursed creature is outside a body of water, the creature takes 6 (1d12) Acid damage at the end of every 10 minutes unless moisture is applied to its skin before those minutes have passed.
Probing Telepathy. If a creature the aboleth can see communicates telepathically with the aboleth, the aboleth learns the creature's greatest desires.
Actions
Multiattack. The aboleth makes two Tentacle attacks and uses either Consume Memories or Dominate Mind if available.
Tentacle. Melee Attack Roll: +9, reach 15 ft. Hit: 12 (2d6+5) Bludgeoning damage. If the target is a Large or smaller creature, it has the Grappled condition (escape DC 14) from one of four tentacles.
Consume Memories. Intelligence Saving Throw: DC 16, one creature within 30 feet that is Charmed or Grappled by the aboleth. Failure: 10 (3d6) Psychic damage.
Success: Half damage. Failure or Success: The aboleth gains the target's memories if the target is a Humanoid and is reduced to 0 Hit Points by this action.
Dominate Mind (2/Day). Wisdom Saving Throw: DC 16, one creature the aboleth can see within 30 feet. Failure: The target has the Charmed condition until the aboleth dies or is on a different plane of existence from the target. While Charmed, the target acts as an ally to the aboleth and is under its control while within 60 feet of it. In addition, the aboleth and the target can communicate telepathically with each other over any distance.
The target repeats the save whenever it takes damage as well as after every 24 hours it spends at least 1 mile away from the aboleth, ending the effect on itself on a success.
Legendary Actions
Aboleth can take 3 Legendary Actions per round, regaining all uses at the start of its turn.
Lash. The aboleth makes one Tentacle attack.
Psychic Drain. If the aboleth has at least one creature Charmed or Grappled, it uses Consume Memories and regains 5 (1d10) Hit Points.
How to run Aboleth
An allied aboleth is a temporary alliance with something that wants to eat your soul later. Set the framing openly: the party has agreed to help the aboleth recover a lost relic, free a rival from imprisonment, or strike at a mind flayer cabal that wronged it centuries ago. The aboleth communicates by telepathy and never leaves its pool, so the alliance is mostly conducted through dominated thralls or through one PC who agreed to be its mouthpiece in exchange for a secret.
In a fight where the aboleth is on side, it will not leave water. Stage the encounter so the party fights on a causeway or shoreline while the aboleth deals with anything that enters the pool. Tentacles drag enemies in, Mucus Cloud curses them, and Dominate Mind turns one of the enemy's heaviest hitters around. The aboleth shares the dominated thrall's senses telepathically, so let one player relay what the dominated enemy sees while the rest of the party fights blind.
The price is the point. Probing Telepathy means the aboleth has read every desire in the party already, and at the end of the favor it asks for one of those desires made explicit. Refuse, and the alliance ends with the aboleth knowing exactly which lever to pull next time. Accept, and write the favor down. Aboleths remember.
Have the aboleth speak only into one PC's mind, never the table's. Players hate being singled out and that's the correct feeling for this monster.
Aboleths don't fight; they negotiate from a position of psychic dominance. The combat round is what happens after the conversation breaks down, and the conversation is the real encounter.
Open with telepathy before initiative. Probing Telepathy fires the moment any character thinks at the aboleth, so you instantly know each PC's greatest desire. Use one of those desires to bait a single character into striking a "deal" before swords come out. If they refuse, the fight begins on your terms, ideally in flooded chambers where Mucus Cloud can do its work and the aboleth's 40 ft. swim trumps the party's wading. The DC 14 Constitution save against the curse is forgiving on the night, but it's the long-term hook for whichever PC fails: every ten minutes outside water, 1d12 acid until they slather on moisture.
In combat, the Multiattack is the engine. Two Tentacle attacks at +9 reach 15 ft. and grapple Large or smaller creatures (escape DC 14), and one of four tentacles can hold each victim. Pair the attacks with Dominate Mind on the party's frontline; once a fighter is Charmed, they're a turret pointed at their own friends, and the save only repeats on damage. Save Consume Memories for a grappled caster, since the 3d6 psychic plus the memory theft is a flavor moment as much as damage. Burn a Legendary Resistance on a cleric's Dispel Magic without hesitation. The aboleth has three uses, four in its lair, and the fight rarely lasts long enough to need them all.
Aboleths do not panic. At 50 HP it slides into the depths, uses Psychic Drain on its way out to recover ground, and triggers Eldritch Restoration if the party somehow scores the kill. That's a 5d10-day reset, which means next session, not this one. Run it patient and certain. It has watched empires rise. It is not going to flinch at a paladin.
Read out the dominated PC's actions in second person to that player without warning, the same voice you use for their character normally. The dissonance lands harder than any saving throw.
Stat block from the System Reference Document 5.2.1 © Wizards of the Coast LLC, used under the Creative Commons Attribution 4.0 license.