Demon, Hydrodemon

Family: Demons

Large fiend (demon), neutral evil

Armor Class 15 (natural armor)
Hit Points 85 (9d10 + 36)
Speed 30 ft., fly 40 ft., swim 60 ft.

18 (+4) 14 (+2) 18 (+4) 8 (-1) 11 (+0) 14 (+2)

Saving Throws Dex +5, Con +7
Skills Perception +6
Damage Resistances cold, fire, lightning
Damage Immunities poison
Condition Immunities poisoned
Senses darkvision 60 ft., passive Perception 16
Languages Abyssal
Challenge 5 (1,800 XP)


  • Amphibious. The hydrodemon can breathe air and water.
  • Magic Resistance. The hydrodemon has advantage on saving throws against spells and other magical effects.
  • Magic Weapons. The hydrodemon’s weapon attacks are magical.
  • Innate Spellcasting. The hydrodemon’s spellcasting ability is Charisma (spell save DC 13, +5 to hit with spell attacks). It can innately cast the following spells, requiring no material components:


  • Multiattack. The hydrodemon makes one Bite attack and two Claws attacks. The demon can use its Sleep Spittle instead of using its Bite.
  • Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) piercing damage, and the target is grappled (escape DC 14). Until this grapple ends, the target is restrained and the demon can’t bite another target.
  • Claws. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 11 (2d6 + 4) slashing damage.
  • Sleep Spittle. One target within 60 feet must succeed on a DC 15 Wisdom saving throw or fall unconscious for one minute. The sleeping target can be awakened if someone uses an action to shake or slap the sleeper awake, and the target wakes if it takes damage.
  • Summon (1/day). The demon chooses what to summon and attempts a magical summoning. A hydrodemon has a 30% chance of summoning a hydrodemon. A summoned demon appears in an unoccupied space within 60 feet of its summoner, acts as an ally of its summoner, and can’t summon other demons. It remains for one minute, until it or its summoner dies, or until its summoner dismisses it as an action.


Hydrodemons are natives of the River Styx and are the only creatures known to possess a natural resistance to the river’s deleterious effects. They are truly massive, standing 10 feet tall at the shoulder, and weigh 4,000 pounds or more. Their green, warty skin serves as an excellent protection, and their sickly yellow eyes take in the world with a baleful malevolence. On the attack, they prefer to glide at their foes and then spit at them. Their spittle causes drowsiness and sleep.

This massive frog-like creature stands nearly 10 feet tall. Its flesh is warty and dark green and its eyes are sickly yellow. It has large flaps of skin under its arms that seemingly function as wings.

Section 15: Copyright Notice

Tome of Horrors 2020, (C) 2020, Necromancer Games

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