Deepwater Leviathans Species in Cathedris | World Anvil

Cathedris Themesong

Deepwater Leviathans

The otherwordly giants of the unfathomable depths

These beautiful creatures were naught but legends for most of our sea-faring history; it's only recently that we've finally discovered that these enigmatic leviathans actually exist.
— Deep Sea Biologist
  Strange, otherworldly, and exceptionally rare -- Deepwater Leviathans are a massive species of jellyfish that inhabit the unfathomable depths of Cathedris's oceans. They are capable of growing to immense size, are seemingly immortal, and have only ever been seen and studied twice in person; yet eye witness sightings throughout the history of many sea-faring civilizations have been the source of countless myths of giant monsters of the ocean.  

Mysteries of the Abyss

The Leviathans grow to be an average of roughly 200m long, with over 70% of that length being their long and tangled mess of tentacles that drift gently behind the massive beasts. They live the absolute majority of their life deep in the ocean, but have very rarely been seen at the surface; only two have ever been seen in modern times.    

Surface Drifter

For about a week a Deepwater Leviathan was found drifting at the surface, in a cold region of ocean to the north of Artazia known as the Ziatic Sea. The specimen was estimated to be 175m long, and there were several species of sharks caught up and slowly digesting within its tentacles; even a Shallow ocean Stoneshark, which was strange given how far away the Leviathan was from the Stoneshark's natural habitat of warmer shallow waters.

Sea-shore Corpse

In the most recent and most beneficial sightings of a Leviathan, one of the massive beasts actually washed up on shore; the only known opportunity for researchers to ever take physical samples of the animal. The massive translucent corpse was partially decayed, having rest on the rocky beach for an unknown amount of time before discovery, and it's thought it could have been around 300m long when it was alive.
by Stormbril with Midjourney
They don't really prey on anything. They just digest whatever happens to drift into their tentacles.
— Deep Sea Biologist
by Stormbril with Midjourney


Deep Ocean
Cold to Warm

Deepwater Expedition

The only living Leviathan ever seen and photographed during modern times was discovered on the maiden voyage of a new experimental vehicle known as an Electrosteel Diveboat. Taking inspiration from the Basalt Divers of the Teneran Deep, this submersible boat was developed; built from thick pressure resistant steel and outfitted with all the latest electrical-tech that Cathedris has to offer.   The craft is capable of remaining under water for up to 3 days, and has a maximum dive depth of 800m -- it has 4 small yet thick reinforced glass windows, and an entire boatload of lights in order to brighten the oppressive darkness below the waves.

Life of Strange Giants

The lifecycle of Deepwater Leviathans is still a complete mystery to marine biologists; the creatures are thought to be essentially immortal with no clear origin, either evolutionary or in terms of direct biological life cycles.
by Stormbril with Midjourney
Additionally, it's hard to tell exactly how old a specimen is, as their bodies do not show signs of aging the same way as most other mortal beings do -- the research done into the samples collected from the Leviathan corpse washed ashore seems to support this hypothesis.   Few guesses exist as to how their life cycle works; it's thought that perhaps they might reproduce asexually, or that there's some connection between them and the Deep Ocean Emerald Egg Sacs that have been mysteriously found, containing strange corrosive gasses.
  A Leviathan's prey appears to be essentially anything and everything that just so happens to be in the wrong place at the wrong time. The tentacles that stretch for hundreds of meters behind the animal's main body exude a naturally corrosive and digestive slime that breaks down most matter that gets tangled within them. These nutrients are then absorbed through the Leviathan's skin, either from direct contact with the prey, or through saturating the water around the beast and allowing it to be absorbed that way.    

As Predator

The animals have grown to be so large and require such low energy to survive that they generally just drift through the sea, consuming whatever gets tangled within their limbs. The relatively high density of their body matter and swirling ocean currents through the depths means that they generally stay quite low, but sometimes drift up if they've gone too long, thought to be hundreds of years without eating. It's thought that as their density and body mass decrease, the Leviathan would drift upwards into more populated waters in order to gorge and regenerate its mass.

As Prey

It's unknown if anything preys on these giant creatures, or if there's anything that can actually even digest its strange body type. Some of the local population from where a Leviathan corpse washed up on shore tried to eat some parts of it, in particular the main body, after they discovered the corrosive slime on the tentacles; but found themselves violently ill for days afterwards. The taste was reported to be strange and metallic, with a chewy yet snappy texture. When cooked, the flesh became rigid and nearly unchewable, with a distinct flavour of bile -- it still made people sick, too.

Honestly, I'm telling the truth! I swear to Sharenskus, I watched one of those Leviathans pull a ship down into the abyss. There was just this disgusting mass of tentacles on the surface of the ocean -- and once the ship touched them, they began to thrash and roil, and the entire vessel began to rapidly sink into the depths.
here for bonus info
— Russin Sailor

by Stormbril with Midjourney

The Origin of Ocean Myth

After the modern day "rediscovery" of the Deepwater Leviathans, their existence began to be tied to countless old myths and legends from around the world, possibly explaining exactly what it was those ancient sailors saw and told fabulous tales about.   Some of the most famous ocean-based mythology that became explained by the Leviathans included classic tales such as "The Gods' Lost Children" that are supposed failed children of the deities before they became husks, "Ocean Beasts" that pull unsuspecting sailors and their entire vessel down to their doom, and "Portals to the Abyss".   This last myth, the portals, is seemingly in reference to a Leviathan's main body cresting the surface of the water while their tentacles swirl around in odd undulating shapes.

Cover image: by Stormbril with Midjourney


Please Login in order to comment!
Jul 17, 2023 16:48 by Dr Emily Vair-Turnbull

Jellyfiiiish. Big jellyfish!   Chewy yet snappable is a texture I can feel. Euuugh. XD

Emy x   Etrea | Vazdimet
Jul 18, 2023 18:10 by Stormbril

That description comes from the one time I tried eating jellyfish :D   Never again :D

Jul 22, 2023 20:52 by Reanna R

Ooh, I like all the mystery surrounding them! Underwater beasts are so cool and terrifying at the same time!

May your worldbuilding hammer always fall true! Also, check out the world of the Skydwellers for lots of aerial adventures.
Jul 24, 2023 16:29 by Stormbril

Yessssss I love deep sea spooky things!

Aug 2, 2023 10:13 by Keon Croucher

I can see the references here, jellyfish and yet giant squid as well, and I love the hybrid idea. The sharks being digested is an interesting touch, implying the tentacles are where it keeps the digestive ability, the corrosives for that, which would indicate it may actually feed less on whole prey as a matter of being an active hunter, and act much more as a natural hazard or booby trap, which then really leads to questions about ships pulled to their doom, and that is an interesting wrench to throw in the spanner of understanding this creature, because how or why would such a thing happen?   I love the imagery, and not just the visible ones, but the ones you add in the writing, especially the little things, like acknowledging in the specimen found dead on shore, it could be even bigger than what people generally think, cause there isn't any real way to know how long it was on shore for, how much it had shrunk under the sun. That is a wonderful and realism building nod, and I appreciate it greatly.   I would like to know a bit more about the corrosive found admist the chemicals, if only because if humans had samples, you know even if we couldn't eat it, we would poke and prod it with all kind of experiments to try and understand it. Is it merely an organic corrosive? Can it etch glass, can it rust or corrode metal or rock? What are the limitations of this chemical compound the creatures produces. Does it react in interesting ways with other known substances? These may not be questions for this article specifically, however such information would allow more knowledge and inferred understanding of the creature, so it would not be out of the realm of reasonable. Regardless if you would consider doing it as part of this article, or its own thing, or leave it be, that is definitely an interesting thread you laid down here that could be utilized in the future should you wish.   All in all a strange, almost alien-esque, and interesting beastie of the deep. :)

Keon Croucher, Chronicler of the Age of Revitalization
Aug 8, 2023 16:50 by Stormbril

ooooooooooo, those are a lot of really good questions! They're absolutely some fun things to think on for perhaps another article in the future :D   The one I'd like to answer here though is on the stories of ships being pulled to their doom -- the way I like to think of it, a Leviathan floated to the surface of the ocean and their tentacles drifted on the top of the water, where some wooden vessel sailed directly into and entangled with them; then the corrosion begins, the ship sinks, and the surviving sailors tell stories of a beast that "pulled" their ship down into the abyss :D   Thank you so much for the lovely comment! <3

Aug 8, 2023 11:21 by E. Christopher Clark

These are awesome and terrifying. I love the idea that they eat whatever is unfortunate enough to get caught in their tentacles, and that image of there being sharks caught in there is not something I can unsee. Well done!

Check out my progress on the Cabinet of Curiosities
Aug 8, 2023 16:51 by Stormbril

Thank you so much Chris! :D These beasties were really fun to imagine and some of their details just seemed to write themselves :D

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