How to Train Your Dragon Wiki
How to Train Your Dragon Wiki

The Luminous Krayfin thrives in a humid habitat and must feed on the Dragon Bloom, a most dangerous flower. Only then can it become a leviathan. Extremely dangerous. Pray you never see this monster on the seas. [src]
  Bork's Papers  

The Luminous Krayfin is a gigantic Tidal Class dragon that first appeared in School of Dragons.

Physical Appearance


Mistery egg.png

The egg of the Krayfin was previously referred to as the "Mysterious Blue Orb" in School of Dragons, before characters understood what it was. It is a large round egg that is a glowing cyan blue in color with darker blue swirls around its circumference.

Hatchling to Adult

The hatchling and Short Wing growth stages of the Krayfin are seen in the School of Dragons expansion, "Secret of the Leviathan". It has four short legs, each ending in a long flipper, and long wings. It is capable of long flight at this age. Its body is rotund and has a chunky short-snouted head. It has a line of luminescent spots trailing along its body. Depending on the lighting within the game, the Krayfin appears to be indigo or dark blue, gray at other times, and even dark green.

According to Hiccup, the Luminous Krayfin grows rapidly.

In the expansion, "Wrath of Stormheart", Fishlegs indicates that a Krayfin's growth is akin to that of a frog, meaning each growth stage physically changes to suit different environments. The hatchling Krayfin is able to live out of water and walk fairly easy, and even fly. However as it matures, the wings elongate and become thinner, more suited for living an entirely aquatic life.

Titan Wing


This growth stage is as yet unknown. However, Bork's Papers reveal that in order for the Krayfin to become a Class 10 Leviathan (Tidal Class term for Titan Wing), it needs to eat a plant called the Dragon Bloom. The Dragon Bloom produces a special fruit that increases the growth speed of the Krayfin.

By the end of the expansion, the Krayfin has grown tremendously, but the player does not know if this is an adult size or still a larger juvenile size.

Based on the Krayfin skeletons underwater at Vanaheim, Lumie is still very small compared to the enormous size of the skeleton.


Speed and Agility

As seen in the "Secret of the Leviathan", the Luminous Krayfin is a very fast swimmer as Lumie was able to swim all the way to Impossible Island in a few minutes after he was scared away.

He is also able to jump from the water and spin in the air, despite his size.


Even as a baby, the Luminous Krayfin is shown to be intelligent, understanding what he can do to help the player through the labyrinth.

Jagged Back

According to Bork's Papers, an adult Luminous Krayfin has a jagged, rocky back that is powerful enough to break a Viking ship in half.

Low-Frequency Sound Production

The Luminous Krayfin is capable of producing low-frequency sounds, similar to those of a whale. This is likely used as a method of communication, as these sounds can easily be heard by other members of the species from miles around.


The Luminous Krayfin gets its name from the bioluminescent lights on its body. These lights likely allow it to see in deep water, though they may also allow it to communicate with other Krayfins in the depths of the ocean.

Sense of Smell

A baby Luminous Krayfin is able to smell a Dragon Bloom from far away and track it down, as seen when one was able to find Impossible Island, a place where a Dragon Bloom grows.

Blinding Flashes

As seen during the "Summarhildr" Expansion Pack, Luminous Krayfins are capable of emitting powerful flashes of light that can temporarily blind their enemies.


Aquatic Adaptations

Though on the one hand adaptations allow the Luminous Krayfin to live successfully in an aquatic environment as an adult, it loses its ability to move well (or at all) on the land and in the air. Since the wing appendages gradually transform into fins, it appears to lose the ability to fly as well.

Behavior and Personality

The one example of a Luminous Krayfin - Lumie - appears quite friendly, peaceful and intelligent. He is able to understand what is needed by his human friends, and get them to follow him. He also makes friends with other dragons as well as local wildlife such as narwhals, another social creature. It is not indicated whether adult Krayfins are solitary or if they live in social groups.


Due to its sociable and intelligent nature, the Luminuous Krayfin appears to be trainable. What is unclear is whether a Krayfin is trainable if raised from an egg or if an adult is also trainable.



School of Dragons

Main article: Lumie

The "Mysterious Blue Orb" (Krayfin Egg) was first seen in the game Expansion "Battle for the Edge". In this expansion, the Dragon Hunters first had it, and later Harald Forkbeard steals it from the Hunters. At this time, the player is not sure what the Orb is.

The "Mysterious Blue Orb" reappears in the next Expansion: "Return to Dragon Island". Through various quests, the player and the Dragon Riders gain control of the Orb, which the player realizes is an egg. The expansion ends with the egg hatching and Hiccup saying his famous line, "This changes everything". The following Expansion, "Secret of the Leviathan", reveals that the egg has hatched into the Luminous Krayfin.

The Luminous Krayfin reappears in the Expansion "Wrath of Stormheart". Fishlegs has been visiting the dragon that hatched out of the "Mysterious Blue Orb" and named him 'Lumie'. Lumie has grown and is able to leave the caldera on Impossible Island. He accompanies the Riders to Vanaheim, where the player discovers a massive skeleton of a Luminous Krayfin off the shores of the island. The player also discovers Nikora's Heirloom on the skeleton.


  • The term "leviathan" seems to be more of a classification based on the sizes of Tidal Class dragons, not to be confused with the actual name of the dragon itself.
  • This dragon is not a rideable dragon at this point in the game. However, if the player leaves and returns to Impossible Island, the dragon can be seen swimming in the lagoon at the bottom and if the player jumps from the bridge and lands on his back, the player won't be forced to respawn on the bridge.
  • The adult form of the Luminous Krayfin resembles a combination of a seal, a sea turtle, and an alligator snapping turtle.
  • The sounds emitted by the baby Luminous Krayfin are the same as Torch's as a baby.
  • The Luminous Krayfin is similar to a Pokémon called "Lapras". Both of them are rare, big, fictional water creatures first seen in a role-playing game. Also, due to the fact that the Pokémon can use dragon-type moves (such as Dragon Dance and Dragon Pulse) it means both are remotely connected to dragons. To the aspect part, both are blue creatures with a long neck in a swan-like pose, flipper-like limbs, a light underbelly, and a brown shell with bumps on which people can sit (although this feature in School of Dragons may be actually a glitch).


Luminous Krayfin uses Creative Commons Licensed content from the Dreamworks School of Dragons Wiki page Luminous Krayfin. The list of authors can be found on the page revision history (view authors). SODWikiLogo.png

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