5E Epic Monsters: Fafnir

Fratricide, patricide, and cursed gold? Dwarf turned dragon!? Inspiration for Smaug!?! I’m sure you know that we’re talking about that envious stout-folk-turned-serpent Fafnir!

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Odin, Loki, and their buddy Hœnir are hanging out and notice this awesome otter, but it’s not actually a fuzzy little animal, it’s Ótr, a dwarf who can shapeshift to take the form of an otter. Loki stones him (the fellow was in animal form) to death and they skin it, showing it off soon after to the dwarf Hreidmar--Ótr’s dad. He is not happy about it and together with his two not-dead sons Fafnir and Regin he captures the trio. In order to set them free, he demands that the otter skin be filled with gold and covered with red gold, and Loki is like “sure I can do that.” The trickster grabs up gold and a magic ring (Andvaranaut) cursed by Andvari with the promise that whoever possessed them was doomed to an early death. Fafnir is fearless and strong of arm but extremely greedy so he kills his father to take all the accursed gold for himself then wanders into the wilds with his ill-gotten gains (where he turns into a dragon to protect it, poisoning everything around him to keep people away).

His brother Regin is greedy too and sends Sigurd (his foster-son) to kill the dragon, giving him a plan to do it: dig pits along a route Fafnir usually travels, hide and then strike from there. Odin stops by and tells Sigurd there’ll be lots of blood so to dig more than one pit, and when Fafnir does appear the warrior lands a critical hit on the dragon’s shoulder. As Fafnir is dying he figures out his brother is to blame for his death, and predicts that Sigurd will suffer a similarly early fate. Sigurd doesn’t much care and has an attitude that everybody dies some day, so why not die rich?

Sigurd also decides to eat the dragon’s heart and when he gets a taste of the Fafnir’s blood while he goes about cooking it, he can suddenly speak to birds--who warn him that Regin is indeed coming to kill him. Sigurd cuts his foster-father’s head off, eats some of Fafnir’s heart, and saves the rest to give to Gudrun after they get married later on.

Design Notes: Slithering poisonous dragon coming right up! I tried to do a catchall with his traits (because surprise surprise there’s more than one version of Fafnir) and have included bits to fit with the Der Ring des Nibelungen operas by Wagner. So I’ve put together a positively toxic serpent here, one without wings that should still make for a compelling fight (with Spew Poison giving it some battlefield control). Definitely going to be using this in a game soon. With that, let’s do the numbers. The DMG lands Fafnir here at 11.333, but the Blog of Holding rubric goes further and hits right onto 13--so I averaged it out at 12.

Huge dragon, neutral evil
Armor Class 18 (natural armor)
Hit Points 168 (16d12+64)
Speed 50 ft., climb 50 ft.
21 (+5)​
20 (+5)​
19 (+4)​
11 (+0)​
12 (+1)​
14 (+2)​
Saving Throws Str +9, Con +8, Wis +5, Cha +6
Skills Athletics +9, Perception +9, Stealth +9, Survival +5
Damage Resistances acid, cold, fire
Damage Immunities poison
Condition Immunities charmed, frightened, poisoned
Senses blindsight 30 ft., darkvision 90 ft., passive Perception 19
Languages Draconic, Dwarvish
Challenge 12 (8,400 XP)

Innate Spellcasting. The dragon’s innate spellcasting ability is Charisma. The dragon can innately cast the following spells, requiring no material components:
At will: speak with animals (birds only)​

Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Mythical Creature. All of the dragon’s attacks are magical and it has advantage on saving throws against spells and other magical effects.

Scorching Blood. Whenever a creature damages the dragon with a melee weapon attack and it is using a weapon that does not have reach, the creature takes 3 (1d6) fire damage.

Multiattack. The dragon can use its frightful presence. It then makes four attacks: one bite, two claws, and one tail slap attack.

Bite. Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 16 (2d10+5) piercing damage.

Claw. Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 19 (1d8+5) slashing damage.

Tail Slap. Melee Weapon Attack: +9 to hit, reach 20 ft., one target. Hit: 14 (2d8+5) bludgeoning damage.

Frightful Presence. Each creature of the dragon’s choice that is within 120 feet and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened for 1 minute. 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 dragon’s frightful presence for the next 24 hours.

Breath Weapons (Recharge 4–6). The dragon uses one of the following breath weapons.
Fire Breath. The dragon exhales fire in 90-foot line that is 5 feet wide. Each creature in that line must make a DC 16 Dexterity saving throw, taking 49 (14d6) fire damage on a failed save, or half as much damage on a successful one.​
Poison Breath. The dragon exhales venomous mist in a 60-foot cone. Each creature in that cone must make a DC 16 Constitution saving throw, taking 49 (11d8) poison damage on a failed save, or half as much damage on a successful one. When a creature has taken 40 poison damage from this attack, it is poisoned until the damage is healed.​

The dragon 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 dragon regains spent legendary actions at the start of its turn.
  • Magic Detection. The dragon makes a Wisdom (Perception) check. This check is made as if the dragon had cast detect magic, though it does not require an action to see magical auras.
  • Spew Poison (Costs 2 Actions). The dragon coughs up a wave of caustic and toxic mucus in a 30-foot cone. All vegetation in the area immediately dies. In addition, for the next minute it becomes difficult terrain and any creature that ends its turn in the area takes 3 (1d6) acid damage and 3 (1d6) poison damage.
  • Tail Attack. The dragon makes a tail slap attack.
Mike Myler



Nice! I was just working on my own version. I like what you did with this, though I think maybe making him tougher (higher AC or HP or both) with a weakness (vulnerable belly) might be more in line with how I remember the story at least. Thank you for sharing.

Mike Myler

Nice! I was just working on my own version. I like what you did with this, though I think maybe making him tougher (higher AC or HP or both) with a weakness (vulnerable belly) might be more in line with how I remember the story at least. Thank you for sharing.
Something like "Weak Belly. A creature targeting Fafnir's vulnerable stomach has disadvantage on its attack roll, but on a successful hit the attack is automatically a critical hit. " ?


Nice one.

Are the breath weapons on separate recharge rolls?

You might want to adjust Spew Poison so that plant creatures take extra damage.

Something like "Weak Belly.
The trick would be to get Fafnir to expose its belly. You'd want to have someone in a pit over which Fafnir slithers or induce Fafnir to rear up, perhaps to attack a flying opponent. Or tossed by a rhino or elephant. I'd suggest this be a reward for teamwork or ingenuity, not simply a mechanical device.

Weak Belly. Fafnir's belly is AC 16 and is Vulnerable to Piercing and Slashing weapons. Fafnir does not ordinarily expose his belly.


I like the legend. I used it as backstory when I created a dwarven artificer for a recent Vikings campaign. Basically, after Fafnir ran off into the wilds but before he turns into a dragon, he meets a kind-hearted maiden and they fall in love, marrying and begetting a son. However, Fafnir's curse turns his love into jealous possessiveness and he locks away his wife and child. Eventually they escape, and his fury and heartbreak help to drive his transformation into a dragon.

My character was the son, Falco Fafnirsson. He bore the Dragonmark of Warding, a birthmark reflecting his father's cursed nature, granting powers relating to guarding and locking away precious treasures.

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