Shah Abbad al-Shaamikh Small humanoid (halfling), lawful evil 6 2,300 xp

Armor class 13 (16) (Armor of Shadows)
Hit points 105 (14d8+42)
Speed 25 ft.

STR 9 (-1)
DEX 16 (+3)
CON 16 (+3)
INT 12 (+1)
WIS 12 (+1)
CHA 18 (+4)

Save Throws: Wis +4, Cha +7

Skills: Arcana +4, Deception +7 History +4, Persuasion +7

Damage Resistances: poison, psychic

Condition Immunities: advantage against being Poisoned and Frightened

Senses: passive Perception 11

Languages: Common, Halfling, Deep Speech, telepathy 30 ft.

Challenge: 6 (2,300 xp)

Aspect of the Moon: The Shah doesn't need to sleep, and can't be forced to sleep by any means.

Actions

Pact Magic (14th-level, Cha-based, +7 hit, DC 15).

--At will: Mage Armor, Levitate, Silent Image, Eldritch Blast (add Cha to damage), Friends, Mage Hand, Minor Illusion, Vicious Mockery, Toll the Dead, Shape Water
--Rituals: Alarm, Purify Food and Drink, Water Breathing, Phantom Steed
--5th-level (3 slots): Witch Bolt, Dissonant Whispers, Charm Person, Mind Spike, Phantasmal Force, Detect Thoughts, Enemies Abound, Hex, Hold Person, Synaptic Static, Dominate Person, Mirror Image

Create Thrall: The Shah touches an incapacitated humanoid, infecting it with Melancholy's alien magic. That creature is Charmed by the Shah until a Remove Curse effect is cast, or the Charmed condition ends. As long as they are on the same plane of existence, the Shah can telepathically communicate with the target.

Dagger: +6 hit, 1d4+3 piercing damage.

Enslaved Villager Small humanoid (halfling), lawful good (lawful evil while charmed by Melancholy) 1/8 25 xp

Armor class 12
Hit points 7 (2d6)
Speed 25 ft.

STR 11 (0)
DEX 14 (+2)
CON 11 (0)
INT 10 (0)
WIS 11 (0)
CHA 10 (0)

Skills: Deception +2, Persuasion +2

Damage Resistances: poison

Condition Immunities: advantage against being Frightened or Poisoned

Senses: passive Perception 10

Languages: Common, Halfling

Challenge: 1/8 (25 xp)

Enslaved: This villager is enslaved by Melancholy the aboleth. It is under Melancholy's control, can't take reactions, and is in constant telepathic communication with the aboleth. Whenever the villager takes damage, it can make a DC 14 Wis save. On a success, it breaks free of Melancholy's control and returns to its own faculties.

Actions

Scimitar: +4 hit, 1d6+2 slashing damage.

Deep Scion Medium humanoid (halfling, shapechanger), lawful evil 3 700 xp

Armor class 13 (leather armor)
Hit points 58 (9d6+27)
Speed 25 ft. (15 ft. and swim 35 ft. in hybrid form)

STR 18 (+4)
DEX 15 (+2)
CON 17 (+3)
INT 10 (0)
WIS 12 (+1)
CHA 14 (+2)

Save Throws: Wis +3, Cha +4

Skills: Deception +6, Insight +3, Sleight of Hand +3, Stealth +3

Damage Resistances: poison

Condition Immunities: advantage against being Frightened or Poisoned

Senses: darkvision 120 ft., passive Perception 11

Languages: Common, Halfling, Deep Speech

Challenge: 3 (700 xp)

Shapechanger (true form: halfling).

Amphibious (hybrid form only).

Actions

Multiattack: In halfling form, the deep scion makes two longsword attacks. In hybrid form, the deep scion makes one bite attack and two claw attacks.

Longsword: +6 hit, 1d10+4 slashing damage.

Bite: +6 hit, 1d4+4 piercing damage.

Claw: +6 hit, 1d6+4 slashing damage.

Psychic Screech (recharges on a short or long rest): The deep scion emits a terrible scream audible within 300 feet. Creatures within 30 feet of the deep scion must make a DC 13 Wis save or be stunned until the end of the scion's next turn. In water, the psychic screech also telepathically transmits the deep scion's memories of the last 24 hours to Melancholy the aboleth, regardless of distance, so long as both of them are in the same body of water.

Sea Spawn Small humanoid, lawful evil 1 200 xp

Armor class 12 (natural armor)
Hit points 32 (5d6+15)
Speed 15 ft., swim 25 ft.

STR 15 (+2)
DEX 10 (0)
CON 16 (+3)
INT 6 (-2)
WIS 10 (0)
CHA 8 (-1)

Senses: darkvision 120 ft., passive Perception 10

Languages: understands Common and Deep Speech but can't speak

Challenge: 1 (200 xp)

Limited Amphibiousness: The sea spawn can breathe air and water, but needs to be submerged in the Oasis of Tears at least once a day for 1 minute to avoid suffocating.

Actions

Multiattack: The sea spawn makes to unarmed strikes and one tentacle attack.

Unarmed Strike: +4 hit, 1d4+2 bludgeoning damage.

Tentacle: +5 hit, reach 10 ft., 1d6+2 bludgeoning damage, and if the target is a Medium or smaller creature it is grappled (escape DC 12). Until the grapple ends, the sea spawn can't use its tentacle on another target.

Chuul Large aberration, lawful evil 4 1,100 xp

Armor class 16 (natural armor)
Hit points 93 (11d10+33)
Speed 30 ft., swim 30 ft.

STR 19 (+4)
DEX 10 (0)
CON 16 (+3)
INT 5 (-3)
WIS 11 (0)
CHA 5 (-3)

Skills: Perception +4

Damage Immunities: poison

Senses: darlvision 60 ft., passive Perception 14

Languages: understands Deep Speech but can't speak

Challenge: 4 (1,100 xp)

Amphibious.

Sense Magic: The chuul senses magic within 120 feet of it at will. This trait otherwise works like the Detect Magic spell but isn't itself magical.

Actions

Multiattack: the chuul makes two pincer attacks. If the chuul is grappling a creature, it can also use its tentacles once.

Pincer: +6 hit, reach 10 ft., 2d6+4 bludgeoning damage, and the target is grappled if it is a Large or smaller creature (escape DC 14). The chuul can only grapple two creatures at a time.

Tentacles: One creature grappled by the chuul must succeed on a DC 13 Con save or be Poisoned for 1 minute. Until this poison ends, the target is paralyzed. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Melancholy Large aberration (aboleth), lawful evil 10 5,900 xp

Armor class 17 (natural armor)
Hit points 135 (18d10+36)
Speed 10 ft., swim 40 ft.

STR 21 (+5)
DEX 9 (-1)
CON 15 (+2)
INT 18 (+4)
WIS 15 (+2)
CHA 18 (+4)

Save Throws: Con +6, Int +8, Wis +6

Skills: History +12, Perception +10

Senses: darkvision 120 ft., passive Perception 20

Languages: Deep Speech, telepathy 120 ft.

Challenge: 10 (5,900 xp)

Amphibious.

Mucous Cloud: Any creature who touches or lands a melee attack against the aboleth while it is underwater and within 5 feet of it must make a DC 14 Con save. On a failure, the creature is diseased for 1d4 hours. The diseased creature can breathe only underwater.

Probing Telepathy: If a creature communicates telepathically with Melancholy, the aboleth learns the creature's greatest desires of it can see the creature.

Actions

Multiattack: Melancholy makes three tentacle attacks.

Tentacle: +9 hit, reach 10 ft., 2d6+5 bludgeoning damage and the target must mae a DC 14 Con save. On a failed save, the creature is diseased. For 1 minute, the disease has no effect and can be removed by any disease-curing magic. After 1 minute, the creature's skin becomes translucent and slimy, and it can't regain hit points unless it is underwater. At this stage, the disease can only be removed by Heal or other disease-curing magic of 6th-level or higher. The diseased creature takes 1d12 acid damage every 10 minutes it is not in contact with water.

Tail: +9 hit, reach 10 ft., 3d6+5 bludgeoning damage.

Enslave (3/Day): 30 foot visual range, one creature must make a DC 14 Wis save or be Charmed by Melancholy until they are on different planes of existence or Melancholy dies. The Charmed target is under Melancholy's control, can't take reactions, and is in constant telepathic communication with Melancholy. The target can repeat the save whenever it takes damage or spends a day more than 1 mile away from Melancholy.

Legendary Actions

Detect: Melancholy makes a Perception check.

Tail Swipe: Melancholy makes a tail attack.

Psychic Drain (Costs 2 actions): One creature charmed by Melancholy takes 3d6 psychic damage, and Melancholy regains hit points equal to the damage the creature takes.