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Deep One Elder

Gargantuan monstrosity (mythos), chaotic evil

Armor Class 19 (natural armor)
Hit Points 232 (15d20+70)
Speed 30 ft., swim 40 ft.

25 (+7) 12 (+1) 21 (+5) 16 (+3) 18 (+4) 16 (+3)

Saving Throws Constitution+11, Wisdom+10, Charisma+9
Skills Religion +8
Damage Resistances acid, cold, lightning; bludgeoning and slashing from nonmagical attacks; Senses passive Perception 14
Languages Common, Deep Speech
Challenge 17 (18,000 XP)

Special Traits

  • Amphibious. The deep one can breathe air and water.
  • Deep Dweller. Deep ones are immune to damage from water pressure; their bodies are capable of instantly adjusting to different water depths or even the surface with ease.
  • Innate Spellcasting. An elder deep one’s spellcasting ability is Wisdom (spell save DC 18). The elder deep one can innately cast the following spells, requiring no material components:
  • Item Use. A deep one can use magic items as though it were a cleric, warlock, or wizard.
  • Legendary Resistance (3/Day). If the elder deep one fails a saving throw, it can choose to succeed instead.
  • Reflective Mind. Any time an elder deep one succeeds at a saving throw against a spell or magical ability that cannot affect creatures that are immune to being charmed or frightened or that inflicts psychic damage, the effect is reflected back on the source, affecting the original caster as if the elder deep one cast the spell or used that magical ability.


  • Multiattack. The elder deep one can use its Awful Presence. It then makes three attacks: one with its bite and two with its claws.
  • Bite. Melee Weapon Attack: +13 to hit, 5 ft. reach. Hit: 16 (2d8 + 7) piercing damage.
  • Claw. Melee Weapon Attack: +13 to hit, 20 ft. reach. Hit: 14 (2d6 + 7) slashing damage. If the elder deep one scores a critical hit, it rolls damage dice three times, instead of twice, and the target must succeed on a DC 21 Constitution saving throw. On a failed saving throw, the target is stunned until the end of their next turn.
  • Awful Presence. Each creature of the elder deep one’s choice that is within 120 feet of the elder deep one and aware of it must succeed on a DC 17 Wisdom saving throw or become frightened for 1 minute. A creature is incapacitated as long as it is frightened in this way. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the elder deep one’s Awful Presence for the next 24 hours.

Legendary Actions

An elder deep one can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The elder deep one regains spent legendary actions at the start of its turn.

  • Claw. The elder deep one makes a claw attack.
  • Madness (Costs 2 actions). All creatures other than deep ones within a 30-foot radius must makes a DC 18 Wisdom saving throw. On a failed saving throw, a creature is affected as the spell confusion until the end of its next turn. Creatures with total cover are not affected.
  • Move. The elder deep one moves or swims up to half its speed without provoking opportunity attacks.
Section 15: Copyright Notice

Pirate Campaign Compendium © 2018, Legendary Games; Lead Designer Jason Nelson. Authors: Alex Augunas, Jeff Gomez, Matt Goodall, Jim Groves, Tim Hitchcock, Victoria Jaczko, Jonathan H. Keith, Lyz Liddell, Thomas J. Phillips, Alistair J. Rigg, Alex Riggs, Loren Sieg, Neil Spicer, Todd Stewart, Rachel Ventura, Michael D. Welham, Linda Zayas-Palmer.