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Troll, Sea

Family: Troll

Large giant, chaotic evil

Armor Class 16 (natural armor)
Hit Points 94 (9d10 + 45)
Speed 30 ft., swim 30 ft.

18 (+4) 14 (+2) 20 (+5) 7 (–2) 9 (–1) 5 (–3)

Skills Perception +2
Senses darkvision 60 ft., passive Perception 12
Languages Giant
Challenge 7 (2,900 XP)


  • Keen Hearing. The sea troll has advantage on Wisdom (Perception) checks that rely on hearing.
  • Regeneration. The sea troll regains 10 hit points at the start of its turn. If the troll takes acid or thunder damage, this trait doesn’t function at the start of the troll’s next turn. The troll dies only if it starts its turn with 0 hit points and doesn’t regenerate.
  • Limited Amphibiousness. The sea troll can breathe air and water but begins to suffocate if not submerged in the sea at least once a day for one minute.


  • Multiattack. The troll makes one Piscine Mutation attack and two Claw attacks.
  • Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage.
  • Piscine Mutations. The sea troll has one or more of the following attack options, provided it has the appropriate anatomy: Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) piercing damage.
  • Poison Quills. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 8 (1d8 + 4) poison damage, and the target must succeed on a DC 12 Constitution saving throw or be poisoned for one minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
  • Tentacle. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 8 (1d8 + 4) bludgeoning damage, and the target is grappled (escape DC 16) if it is a Medium or smaller creature.


Sea trolls live near the large bodies of water of the world. Due to mutations, sea trolls have become viable hunters on land and in the water. Those that have mostly piscine diets have even taken on some of the physical traits of their prey (see Piscine Mutations under Actions). Due to their extended time spent in the water, sea trolls have a heightened sense of hearing similar to echo location instead of smell. Their bodies are more resistant to fire as well. However, they are vulnerable to thunder damage, so much so that it arrests the regenerative properties of their flesh.

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