Ceffyl Dwr

Large fey (mount, shapechanger), chaotic neutral

Armor Class 17 (natural armor)
Hit Points 51 (6d10 + 18)
Speed 60 ft., climb 30 ft., swim 40 ft. , fly 60 ft.

18 (+4) 15 (+2) 16 (+3) 14 (+2) 12 (+1) 18 (+4)

Skills Insight +3, Deception +6, Perception +3, Performance +6, Stealth +4
Damage Immunities poison; bludgeoning, piercing, and slashing from nonmagical attacks that aren t iron
Condition Immunities poisoned, prone
Senses darkvision 60 ft., passive Perception 13
Languages Common, Sylvan
Proficiency Bonus +2
Challenge 4 (1,100 XP)


  • Amphibious. The ceffyl dwr can breathe air and water.
  • Fey Ancestry. The fey has advantage on saving throws against being charmed, and magic can’t put it to sleep.
  • Glowing. The ceffyl dwr sheds dim light within 20 feet of itself.
  • Misty Escape. When it drops to 0 hit points outside its resting place, the ceffyl dwr transforms into a cloud of mist (as in the Shapechanger trait) instead of falling unconscious. While it has 0 hit points in mist form, it can’t revert to its other forms, and it must reach its resting place within 2 hours or be destroyed. Once in its resting place, it reverts to its Horse form. It is then paralyzed until it regains at least 1 hit point. After spending 1 hour in its resting place with 0 hit points, it regains 1 hit point.
  • Saddle. The ceffyl dwr can wear a saddle on its back. One Medium or two Small creatures can sit on the saddle without squeezing. To make a melee attack against a target within 5 feet of the ceffyl dwr, they must use spears or weapons with reach. If the ceffyl dwr dies, creatures hanging fall straight down, taking falling damage, and land in unoccupied spaces within 5 feet of the ceffyl dwr’s position on the ground.
  • Sticky. The ceffyl dwr has advantage on Strength (Athletics) checks made to grapple and any ability check made to maintain a hold on another creature, a surface, or an object. The ceffyl dwr can also climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.


  • Multiattack. The ceffyl dwr makes two melee attacks: two with its Battleaxe in humanoid form or one with its Bite and one with its Hooves in horse form.
  • Battleaxe (Humanoid Form Only). Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) slashing damage, or 9 (1d10 + 4) slashing damage if used with two hands.
  • Bite (Horse Form Only). Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 6 (1d4 + 4) piercing damage.
  • Hooves (Horse Form Only). Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage.
  • Charm. One humanoid the ceffyl dwr can see within 30 feet of it must succeed on a DC 14 Wisdom saving throw or be magically charmed for 1 day. The charmed target obeys the ceffyl dwr’s verbal or telepathic commands. If the target suffers any harm or receives a suicidal command, it can repeat the saving throw, ending the effect on a success. If the target successfully saves against the effect, or if the effect on it ends, the target is immune to this ceffyl dwr’s Charm for the next 24 hours. The ceffyl dwr can have only one target charmed at a time. If it charms another, the effect on the previous target ends.


  • Trampling Charge (Horse Form only). If the ceffyl dwr moves at least 20 feet straight toward a creature and then hits it with a hooves attack on the same turn, that target must succeed on a DC 14 Strength saving throw or be knocked prone. If the target is prone, the ceffyl dwr can make another attack with its bite against it as a bonus action.
  • Change Shape. The ceffyl dwr can polymorph into a humanoid (30 ft.), a Medium cloud of mist, or back into its true form. Its statistics, other than its speed, are the same in each form. Any equipment it is wearing or carrying isn’t transformed. The ceffyl dwr reverts to its true form if it dies. While in mist form, the ceffyl dwr can’t take any actions, speak, or manipulate objects. It is weightless, has a flying speed of 20 feet, can hover, and can enter a hostile creature’s space and stop there. In addition, if air can pass through a space, the mist can do so without squeezing, and it can’t pass through water. It has advantage on Strength, Dexterity, and Constitution saving throws, and it is immune to all nonmagical damage.


  • Sticky Hide. When a creature misses the ceffyl dwr with a melee weapon attack, it sticks to the ceffyl dwr’s hide. The attacker must succeed on a DC 14 Strength saving throw, or the weapon becomes stuck to the ceffyl dwr’s hide. If the weapon’s wielder can’t or won’t let go of the weapon, the wielder is grappled while the weapon is stuck. While stuck, the weapon can’t be used. A creature can pull the weapon free by taking an action to make a DC 14 Strength check and succeeding.


This unearthly winged horse has a near translucent hide that ripples like a morning mist.

The ceffyl dwr (KEF-fil-DJOR), also known as the Water Horse, is a fey creature with the ability to shapeshift. Ceffyl dwrs are typically found in mountain ponds, waterfalls, rivers, and marshes. They are particularly drawn to areas with abundant water sources, and they define one body of water (at least pond-sized) as their resting place. These creatures have a unique connection to water and are able to move through it with great agility and speed.

Ceffyl dwrs are known for their enigmatic nature. They are generally considered to be peaceful creatures, though they can become aggressive if provoked. They are associated with the Unseelie Court, exhibiting both human and waterhorse behaviors. They possess the ability to shapeshift between humanoid and horse forms, allowing them to blend in with human society. In their horse form, they are sleek and stealthy, able to move swiftly through the water and even climb difficult surfaces. Ceffyl dwrs are known for their stickiness, which aids them in grappling and maintaining holds on creatures, surfaces, or objects.

Ceffyl dwrs are predatory creatures that consume humans and other beings for sustenance. While they are generally peaceful, they can turn aggressive and attack lone travelers or those who provoke them. They have been known to trample their victims to death or lure them into riding on their backs, only to drown or drop them from great heights. Some legends describe their ability to charm and control their victims, forcing them to move closer to the ceffyl dwr. The ceffyl dwr is a formidable foe, using its physical attacks and its sticky hide to incapacitate and restrain its prey.

Section 15: Copyright Notice

5E RPG: Celtic Bestiary. Copyright 2023, Mal and Tal Enterprises, LLC; Author Michael Tresca.

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