100 Aquatic Enemies for 1st-5th level Characters

In this series I will be presenting creatures you can use for villains, lieutenants, minions, and wild encounters for 5th edition aquatic games. I will also be presenting encounter seeds for these villains at each tier. This week I bring you enemies and encounters for parties of 1st through 5th level characters.

Though these monster lists and story seeds are inspired by 5th edition, they can be used as adventure ideas for any fantasy RPG.

Make sure to check out Shawn Ellsworth’s overview of 10 Awesome Monsters for Aquatic Encounters, as well as his articles for eight other terrains right here on Tribality.

Looking for encounter ideas for these creatures? There are over a dozen for you right here.

Villains

For the purposes of this series, villains are defined as individuals that act as either instigators of complex local, city-wide, or country-wide plots, or creatures that can act as the main antagonist for one or more adventures. I’ve typically limited Villains to creatures with a minimum of 10 Intelligence. This led me to some surprising discoveries. For example, I didn’t realize that several low-level undead creatures have impressive Intelligence scores, including banshees, ghosts, ghasts, revenants, wraiths, and even will-o’-wisps!

I’ve also included a few surface creatures that make excellent villains and can be easily adapted to an aquatic campaign (such as the mind flayers and yuan-ti), as well as one or more new villains for you to use against your party.

Bonus Villain: by popular demand, the wereshark.

Lieutenants

Lieutenants act as the higher-level minions of villains. They are smart enough to instigate plots of their own, typically at the behest of their villainous masters. Alternately, lieutenants may act as Villains for the lowest level parties at each tier. For example, a young black dragon (CR 7) can act as a main villain for a party of 6th level PCs, as long as it has enough minions and an interesting enough lair to make the encounter enjoyable.

Bonus Lieutenant: a new, CR 4 merrow: the hunter-seeker

Minions/Pets

Minions are the lowest-tier servants of the villains and lieutenants, or beasts that can be used as wandering monsters, guards, or random encounters. Lieutenants (and even Villains) of lower-level parties can easily be the Minions of higher-level Villains. This category also includes creatures with Intelligence scores below 10, including beasts, constructs, plants, and undead that can be used to flesh out encounters.

Keep in mind that large numbers of lower CR creatures can also make for interesting encounters. For example, sharks make great encounters in small numbers, but some species of sharks, including the hammerhead (use stats for hunter shark) swim in shoals of hundreds and even thousands! Though a combat using 100 hunter sharks might appear tedious, it can be a terrifying experience and a challenge for any party. At 45 hit points and 13 damage per bite, even these CR 2 creatures can deal significant damage to 11th level or higher PCs, especially after a party member gets damaged and triggers the shark’s blood frenzy.

Since the Lieutenants (and even Villains) of lower-tiers can be used as Minions in higher-level encounters, there is plenty of material to use. I have, however, included one or more new creatures you can use against your players when inspiration has hit.

Encounters

In the accompanying article for each tier, I will provide general plot outlines and story seeds for you to use to create encounters for your aquatic games. I will include options for campaigns focused entirely on aquatic races as well as for surface campaigns looking to shake things up.

Though these lists and story seeds are inspired by 5th edition, they can be used to inspire adventures for any fantasy RPG.


1st-5th Level

Villains

Challenge Rating 2
  • Bandit Captain (koalinth, kuo-toa, locathah, lizardfolk, merfolk, sahuagin; replace scimitar with shortsword or trident)
  • Berserker (koalinth, kuo-toa, locathah, lizardfolk, merfolk, sahuagin; replace great axe with the manifested natural weapons of a totem animal, damage remains the same)
  • Cult Fanatic (add dark devotion and spell casting to any CR 1 or less lieutenant/minion with Intelligence and Wisdom of 10 or higher)
  • Druid (can be of any aquatic race or creature capable of having an Intelligence and Wisdom of 12 or higher; replace quarterstaff with spear)
  • Priest (can be of any aquatic race or creature capable of having an Intelligence and Wisdom of 12 or higher; replace mace with shortsword or trident)
  • Ghast
Challenge Rating 3
  • Hag, Green
Challenge Rating 4
  • Banshee
  • Ghost
  • Lizardfolk King/Queen
Challenge Rating 5
  • Half-dragon Veteran (Black/Green) (add Amphibious trait)
  • Lycanthrope, Wereshark (see below)
  • Revenant
  • Sahuagin Baron
  • Wraith
Challenge Rating 6
  • Mage (can be of any aquatic race or creature capable of having an Intelligence of 16 or higher; increase CR by 1 if already greater than 6)
  • Koalinth Warlord (hobgoblin warlord with the Amphibious trait; Swim speed 40 feet)
  • Kuo-Toa Archpriest
Challenge Rating 7
  • Black Dragon, Young
  • Mind Flayer (add Amphibious or Water Breathing traits)
  • Yuan-Ti Abomination (add the Amphibious or Water Breathing traits; add Swim speed 40’)
Challenge Rating 8
  • Green Dragon, Young 

Lieutenants

Challenge Rating 1
  • Kuo-Toa Whip 
Challenge Rating 2
  • Black Dragon, Wyrmling 
  • Druid (can be of any aquatic race or creature capable of having an Intelligence and Wisdom of 12 or higher; replace quarterstaff with spear)
  • Ghast
  • Green Dragon, Wyrmling
  • Lizardfolk Shaman
  • Merrow
  • Priest (can be of any aquatic race or creature capable of having an Intelligence and Wisdom of 12 or higher; replace mace with shortsword or trident)
  • Sahuagin Priestess
  • Sea Hag
  • Will-o’-Wisp
Challenge Rating 3
  • Doppelgänger (add Amphibious trait, or use shapeshifting ability)
  • Koalinth Captain (hobgoblin captain with the Amphibious trait; Swim speed 40 feet)
  • Kuo-Toa Monitor
  • Wight
  • Yuan-Ti Malison (add the Amphibious or Water Breathing traits; add Swim speed 30’; merfolk features in place of human features)
Challenge Rating 4
  • Naga, Bone
  • Ghost
  • Merrow, Hunter-Seeker (see below)
Challenge Rating 5
  • Gladiator (koalinth, kuo-toa, locathah, lizardfolk, merfolk, sahuagin)
  • Lycanthrope, Wereshark (see below)

Minions/Pets

Challenge Rating 1/8
  • Locathah
  • Locathah, Cultist (add dark devotion)
  • Merfolk
  • Merfolk, Cultist (add dark devotion)
  • Noble (merfolk, locathah)
  • Snake, Poisonous (add Amphibious trait)
  • Tribal Warrior (merfolk, locathah)
Challenge Rating 1/4
  • Acolyte (koalinth, kuo-toa, locathah, merfolk, sahuagin; replace club with dagger)
  • Bullywug
  • Cultist (add dark devotion to any CR 1/4 minion with Intelligence and Wisdom of 10 or higher)
  • Frog, Giant
  • Kuo-Toa
  • Kuo-Toa, Cultist (add dark devotion)
  • Mephit, Mud (Add Amphibious trait)
  • Mephit, Steam (add Amphibious trait)
  • Pseudodragon (add Amphibious or Aquatic traits)
  • Skeletons (add Swim 10’, without flesh, skeletons are poor swimmers)
  • Snake, Giant Poisonous (add Amphibious trait)
  • Snake, Constrictor (add Amphibious trait)
  • Zombie (if an aquatic-race zombie, add Swim speed equal to 10 feet less than the race’s swim speed. If a land-race zombie, add a Swim speed of 10 feet, but allow them to move along the bottom of a body of water at their normal walking speed.)
Challenge Rating 1/2
  • Cultist (add dark devotion to any CR 1/2 minion with Intelligence and Wisdom of 10 or higher)
  • Crocodile
  • Koalinth (hobgoblin with the Amphibious trait; Swim speed 40 feet)
  • Koalinth, Cultist (add dark devotion)
  • Lizardfolk
  • Lizardfolk, Cultist (add dark devotion)
  • Mephit, Ice 
  • Sahuagin
  • Sahuagin, Cultist (add dark devotion)
  • Scout (koalinth, kuo-toa, locathah, merfolk, sahuagin; replace shortbow with light crossbow)
  • Shadow 
  • Shark, Reef 
  • Thug (koalinth, kuo-toa, locathah, merfolk, sahuagin)
  • Vine (Seaweed) Blight (add Amphibious or Water Breathing traits; Swim speed 10 feet)
Challenge Rating 1
  • Ghoul 
  • Octopus, Giant 
  • Quipper, Swarm 
  • Specter
  • Spy (koalinth, kuo-toa, locathah, merfolk, sahuagin (malenti))
  • Toad, Giant
  • Yuan-Ti Pureblood (add the Amphibious or Water Breathing traits; add Swim speed 30’; use merfolk features in place of human features.)
Challenge Rating 2
  • Druid (can be of any aquatic race or creature capable of having an Intelligence and Wisdom of 12 or higher; replace quarterstaff with spear)
  • Constrictor Snake, Giant (add Amphibious trait)
  • Merrow 
  • Ooze, Ochre Jelly (add trait that oozes do not require air)
  • Plesiosaurus 
  • Poltergeist (see Ghost)
  • Priest (can be of any aquatic race or creature capable of having an Intelligence and Wisdom of 12 or higher; replace mace with shortsword or trident)
  • Shark, Hunter 
  • Snak, Poisonous Swarm
  • Will-o’-Wisp 
Challenge Rating 3
  • Knight (koalinth, kuo-toa, locathah, lizardfolk, merfolk, sahuagin; replace greatsword with trident)
  • Veteran (koalinth, kuo-toa, locathah, lizardfolk, merfolk, sahuagin; replace longsword with extra shortsword, or both swords with trident)
  • Water Weird 
Challenge Rating 4
  • Ooze, Black Pudding (add trait that oozes do not require air)
Challenge Rating 5
  • Crocodile, Giant
  • Gladiator (koalinth, kuo-toa, locathah, lizardfolk, merfolk, sahuagin)
  • Scrags (trolls with the Amphibious or Water Breathing traits)
  • Shark, Giant
  • Shambling (Seaweed) Mound (add Amphibious or Water Breathing traits; Swim speed 30 feet)
  • Umber Hulk (add Amphibious or Water Breathing traits; Swim speed 30 feet)
  • Water Elemental

Merrow Hunter-Seeker

Large monstrosity, chaotic evil

Armor Class 15 (natural)
Hit Points 76 (8d10+24)
Speed 10 ft.; swim 40 ft.
Initiative +5
_______

Str 18 (+4) Dex 14 (+2) Con 16 (+3) Int 10 (+0) Wis 14 (+2) Cha 13 (+1)
_______

Skills Intimidate +7, Perception +8, Stealth +5, Survival +5
Senses blindsight 60 ft., darkvision 60 ft., Passive Perception 18
Languages Abyssal, Aquan
Challenge 4 (1,100xp)

_______

Amphibious. The hunter-seeker can breath both air and water.
Echolocation. The hunter-seeker looses its blindsight ability while deafened and its range is reduced to 15 feet when out of water.
Blood Track. The hunter-seeker can detect even small amounts of blood from huge distances. The hunter-seeker may track creatures through open water and makes all checks to track creatures at advantage as long as the target has less than maximum hit points. This ability only works underwater.
Blood Frenzy. The hunter-seeker gains advantage on attacks against any creature at less than maximum hit points.
_______

Actions

Multiattack. The hunter-seeker makes two attacks: one with its bite and one with its claws or harpoon.

Bite. +7 to hit, reach 5 ft., one target,  14 (2d8+4) piercing damage.

Claws. +7 to hit, reach 5 ft., one target,  12 (2d6+4) slashing damage.

Harpoon. +7 to hit, reach 5 ft. or range 20/60 ft., one target,  14 (2d8+4) piercing damage and the target must succeed on a DC 13 Dexterity saving throw or become impaled. An impaled creature is restrained. A critical hit forces the target to make the Dexterity save at disadvantage. If an impaled creature is Huge or smaller, it must succeed on a Strength contest against the hunter-seeker or be pulled up to 20 feet toward the hunter-seeker. The hunter-seeker may not make a harpoon attack as long as a target is impaled. The impaled creature, or any creature adjacent to them, may use an action to end the restrained condition. Doing so inflicts an additional 14 (2d8+4) piercing damage. The damage can be prevented by a successful DC 15 Medicine check made after 1 minute of treatment.


Lycanthrope, Wereshark

Medium humanoid (humanoid, shapechanger), chaotic neutral

Armor Class 10 in humanoid form, 12 (natural armor) in shark or hybrid form
Hit Points 135 (18d8+54)
Speed 30 ft. (30 ft., swim 30 ft. hybrid; 0 ft., 40 ft. shark)
Initiative +4
_______

Str 18 (+4) Dex 14 (+2) Con 16 (+3) Int 10 (+0) Wis 12 (+1) Cha 13 (+1)
_______

Skills Perception +7
Senses Passive Perception 17
Languages Aquan, Common (can’t speak in shark form)
Challenge 5 (1,800xp)

_______

Shapechanger. The wereshark can use its action to polymorph into a Large shark-humanoid hybrid or into a Large shark, or back into its true form, which is either humanoid or piscinoid. Its statistics, other than its size, speed, and AC, are the same in each form. Any equipment it is wearing or carrying isn’t transformed. It reverts to its true form if it dies.
Amphibious.
 In hybrid form, the wereshark can breath both air and water.
Water Breathing. In shark form, the wereshark can breath only water.
Electroreception. In hybrid or shark form, the wereshark gains blindsight 30 feet. This ability detects only living creatures, objects powered by electricity, and electrical spell effects. The wereshark loses this ability for 1 round after taking lightning damage.
Blood Track. The wereshark can detect even small amounts of blood from huge distances. The wereshark may track creatures through open water and makes all checks to track creatures at advantage as long as the target has less than maximum hit points.
Blood Frenzy. The wereshark gains advantage on attacks against any creature at less than maximum hit points.
_______

Actions

Multiattack. In shark form, the wereshark makes two bite attacks. In humanoid form, it makes two attacks with its trident. In hybrid form, it can attack like a shark or humanoid.

Bite. +7 to hit, reach 5 ft., one target,  15 (2d10+4) piercing damage. If the target is a humanoid, it must succeed on a DC 14 Constitution saving throw or be cursed with wereshark lycanthropy.

Trident. +7 to hit, reach 5 ft. or 20/60 ft., one target, 9 (1d8+4) piercing damage.

Harpoon. You may substitute a harpoon for the trident. See the merrow hunter-seeker above.


Featured wereshark miniature image from Leisure Games.
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richhoward

Rich Howard's obsession with gaming started 35 years ago when his older brother finally let him invade his AD&D game. Since his first sleep spell, Rich has wandered the world of roleplaying, board and computer games as fascinated with their potential to teach and inspire as to entertain.