AC 13
HP 85 (10d10 + 30; bloodied 42)
Speed 30 ft., swim 30 ft.
Proficiency +2; Maneuver DC 13
Skills Deception +6, Perception +5, Stealth +5
Senses darkvision 60 ft., passive Perception 15
Languages Abyssal, Common
Chaotic Evil. The giant lanternfish radiates a Chaotic and Evil aura.
Innate Spellcasting. The giant lanternfish’s innate spellcasting ability is Charisma (spell save DC 14). It can innately cast the following spells, requiring no material components.
At will: charm person , disguise self (humanoid form), major image , misty step
1/day each: geas , hallucinatory terrain , hypnotic pattern , scrying
ACTIONS
Dizzying Touch. Melee Spell Attack: +6 to hit, reach 5 ft., one creature. Hit: The target is magically charmed for 1 hour or until it takes damage. While charmed in this way, it has disadvantage on Wisdom saving throws and ability checks.
Claws. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 17 (4d6 + 3) slashing damage.
Dagger. Melee or Ranged Weapon Attack: +5 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 5 (1d4 + 3) piercing damage, and the target makes a DC 13 Constitution saving throw . On a failure, the target takes 10 (3d6) poison damage and is poisoned for 1 hour.
Hypnotic Pattern (3rd-Level; S, Concentration). A swirling pattern of light appears at a point within 120 feet. Each creature within 10 feet of the pattern that can see it makes a DC 14 Wisdom saving throw . On a failure, the creature is charmed for 1 minute. While charmed, the creature is incapacitated and its Speed is 0. The effect ends on a creature if it takes damage or if another creature uses an action to shake it out of its daze.
BONUS ACTIONS
Misty Step (2nd-Level; V). The giant lanternfish teleports to an unoccupied space it can see within 30 feet. The giant lanternfish can’t cast this spell and a 1st-level or higher spell on the same turn.
Combat
Lanternfish avoid melee combat, sending their servants to fight for them while they use hypnotic pattern and throw daggers at their enemies from a distance. When cornered, they claw their foe and escape with misty step .
In the darkest depths of the sea swim giant, intelligent, carnivorous fish that lure prey with the bioluminescent lights on their foreheads. They can transform into merfolk or sea elf guises, but in any form they always hold a light source: a giant glowing pearl, a luminescent jellyfish, a sea-coal-burning lantern, or the like. Giant lanternfish surround themselves with charmed merfolk and send merrow to do their bidding.
1 in humanoid form, lounging on a throne or sofa, eager to speak with travellers
2 in humanoid form: chooses a member of the party to entice with gifts and praise
3 in true form, surrounded by geased merfolk slaves
4 in humanoid form, pretending to be the prisoner of an evil tyrant (who is actually a charmed noble )
5 with a defiant holy knight in a cage: the lamia hasn't been able to corrupt the knight so far
6 about to pit two geased prisoners against one another, unless you provide some other amusement
Lanternfish rule underwater caverns and ruins.
CR 5–10 Lamia with 1 or 2 lions and 1d8 + 2 commoners , or lamia with 1 or 2 giant constrictor snakes and 1d6 + 2 guards , or lamia with 1d8 + 3 jackalweres and 1d6 nobles , or lamia with doppelganger and 6 jackalweres , or lamia with manticore
Treasure 1,200 gp, 500 ep, 2,500 sp, silver throne (750 gp), golden demon idol (750 gp), potion of clairvoyance , staff of the python