Leviathan
Leviathan — The Encounter
The sea's first predator, coiling king of the deep · a boss your table can run with almost no prep. SRD 5.1-compatible.
Who Is Leviathan
Before the gods drew breath, the deep already had a king. The leviathan is the ocean's first predator, a serpent so vast that mariners charted its barnacled back as an island and named its exhalations weather. Its belly is crusted with the shells of ten thousand years; its flanks are smooth hydrodynamic plate that no harpoon has scarred. Old scripture warns that none is so fierce as to rouse it, that it makes the deep boil like a pot and leaves a shining wake behind it. Sailors who have seen the crown of bony ridges rise from the swell speak of an intelligence in those cold eyes, patient and pitiless. It does not hunt for hunger alone. It hunts because the sea is its dominion and every keel that crosses it is a trespass. To meet the leviathan is to learn, in one breaching instant, that the ocean was never your friend.
Run Leviathan in Sixty Seconds
- It is a solo boss. Built to run alone with legendary actions; do not add other big threats or you will overwhelm an 11th-level party.
- Open from underwater. Lead with Breaching Surge or Swallowing Tide on whoever is bunched up; prone-and-pushed targets land in difficult-terrain water.
- Kill-priority: the boat and the swimmers. Tail-push and grapple to drag fragile PCs off the deck and into the sea, then Bite the grappled one.
- When bloodied (99 HP), it dives. Use Sounding Dive and Surge to reposition, striking from a new edge each round so melee can never pin it.
- Three ways to run it: a fleeing hit-and-submerge chase (T1), a reef ambush with hazards (T2), or a full legendary breach-and-drown set piece (T3).
Leviathan
Huge dragon, neutral evil
CR 11 · 7,200 XP · GUIDELINEHold Breath. The leviathan can hold its breath for 1 hour and is amphibious enough to breach onto land for short, devastating strikes.
Breaching Surge. Signature. On a turn the leviathan moves at least 30 ft. through water before attacking, its bite deals an extra 14 (4d6) bludgeoning damage and the target must succeed on a DC 16 Strength save or be knocked prone and pushed 10 ft.
Foundering Wake. Water within 30 ft. of the leviathan is difficult terrain for other creatures, and vehicles in that area move at half speed against the churning swells.
Actions
Multiattack. The leviathan makes one Bite attack and one Tail attack. It can use Swallowing Tide (recharge 5-6) in place of its Bite.
Bite. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 27 (4d8+7) piercing damage. A Large or smaller target hit must succeed on a DC 16 Dexterity save or be grappled (escape DC 16).
Tail. Melee Weapon Attack: +9 to hit, reach 20 ft., one target. Hit: 20 (3d8+7) bludgeoning damage and the target is pushed 15 ft. away from the leviathan.
Swallowing Tide (Recharge 5-6). The leviathan crashes down in a 30-foot cone of crushing seawater. Each creature there makes a DC 16 Strength save, taking 36 (8d8) bludgeoning damage and being knocked prone on a failure, or half damage on a success.
Bonus Actions & Reactions
Sounding Dive (Reaction). When hit by a melee attack while in water, the leviathan can submerge, halving the damage and moving up to half its swim speed without provoking opportunity attacks.
Legendary Actions (3/Round)
Lash. The leviathan makes one Tail attack.
Surge (Costs 2 Actions). The leviathan swims up to its swim speed. If it passes through a creature's space, that creature makes a DC 16 Strength save or is knocked prone and takes 9 (2d8) bludgeoning damage.
Drowning Roar (Costs 2 Actions). The leviathan bellows. Each creature within 30 ft. makes a DC 16 Constitution save or is deafened and has disadvantage on attack rolls until the end of its next turn.
Sculpted at the instant of breaching, thousands of tons of primordial muscle erupt from the waterline, jaws wide enough to swallow a longship whole, a crown of bony ridges hinting at something far older than any land-born thing.
Leviathan, Bound
Companion · acts on your initiative
Bound · GUIDELINETide-Tethered (signature). While within 60 ft. of the leviathan, the thrall has advantage on saving throws against being frightened and can breathe water.
Actions
Barbed Gaff. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 14 (2d8+5) piercing damage, and a grappled target is dragged 10 ft. toward the water.
Reactions
Undertow Guard. When the leviathan would be hit by an attack, the thrall within 5 ft. of it can interpose, taking the damage instead.
A drowned sailor reanimated by the deep's will, lashing intruders toward the water so its master can feed.
Guideline numbers — formula-tuned and read from the miniature's design, not yet table-proven. Tell us how it ran in the comments.
How It Fights — by Tier
Same creature, scaled threat. The traits never change; only the numbers move.
A juvenile leviathan; open by breaching for the Bite, then Tail-slap to scatter the cluster. Kill-priority is whoever clings to a boat or shoreline, since prone-and-pushed targets fall in the water. At this scale run it as a fleeing chase boss, not a stand-and-fight.
Open with Breaching Surge into the densest knot of swimmers, then save Swallowing Tide for when three or more are clumped. Use Sounding Dive every time a heavy hitter lands a melee blow. Pair it with reef hazards or a brine-thrall escort to split the party's attention.
Full solo boss: open with Swallowing Tide on the clustered front line, then Multiattack the grappled target. Spend legendary actions on Surge to knock prone-and-trample, and Drowning Roar when the ranged casters group up. Kill-priority is anyone keeping the party afloat; dump them in the difficult-terrain water and let the wake do the rest.
Put Leviathan on the table
Download the presupported STL and run the fight tonight — the model, and the encounter that comes with it.
Get the STL on MyMiniFactory →Clay Cyanide Companion Rules v1
How a bound creature acts
- A companion acts on its owner's initiative, immediately after the owner.
- It uses the Companion block above — roughly ×0.6 HP and damage, no recharge abilities, and at most one reaction trait.
- It moves freely; it takes its Action only while its owner is conscious.
- At 0 HP a companion is broken, not dead — restored on a long rest unless your table rules otherwise.
Original Clay Cyanide material © Clay Cyanide LLC — explicitly not the non-SRD official sidekick rules.
Questions, Asked at the Table
What CR is Leviathan?
Natively CR 11 (Tier 3) as a solo, legendary sea-monster boss. Because its legendary actions and reaction let it play up a band, its sheet drops one tier from a pure brawler of its size. Scaled stat blocks are provided for level 1-4 and 5-10 parties as well.
Can Leviathan be a companion or ally?
Not as a player ally; it is a primordial apex predator that recognizes no master. For an allied or summoned theme use the Brine-Drowned Thrall companion block, a drowned sailor bound to the leviathan's will that drags foes toward the water.
How do I keep the fight from being a slog at sea?
Give the party something to defend (a ship, a reef, survivors) so they cannot simply swim away, and lean on Tail-push and grapple to keep moving bodies into the water. The Swallowing Tide cone and difficult-terrain wake punish clustering, so reward players who spread out.
Tell Us How It Ran
This work includes material taken from the System Reference Document 5.1 ("SRD 5.1") by Wizards of the Coast LLC and available at dnd.wizards.com/resources/systems-reference-document. The SRD 5.1 is licensed under the Creative Commons Attribution 4.0 International License available at creativecommons.org/licenses/by/4.0/legalcode.
Clay Cyanide Miniatures is not affiliated with, endorsed, sponsored, or specifically approved by Wizards of the Coast LLC. This content is compatible with the fifth edition of the world's most popular fantasy roleplaying game. Companion rules, lore, names, and original mechanics © Clay Cyanide LLC.
The Legend
In Your Campaign
CR Range: 20+ (legendary sea monster)
Encounter Design: The Leviathan works best as a set-piece encounter aboard a ship. It can swallow vessels, create massive waves as legendary actions, and summon storms. Don't fight it — survive it. Give the party an objective (reach the island, protect the cargo, rescue someone from the water) while the Leviathan treats the ship as a chew toy.
Campaign Hooks: Blocks a critical sea route. Awakened by deep-sea mining. Called by a cult to destroy a coastal city. The party must negotiate with it — because it can speak.
Technical Specifications
32mm, 75mm
STL, Pre-supported STL
Standard or ABS-like resin, 0.05mm layer height
Yes — ready to print, optimized supports included
From the Same Collection
Frequently Asked Questions
How large is the Leviathan at 75mm scale?
At 75mm display scale, the Leviathan spans approximately 8-10 inches. It is one of the largest models in the Clay Cyanide catalog and makes an exceptional display centerpiece.
Can the Leviathan be used in naval combat scenarios?
Absolutely. The Leviathan is designed for dramatic sea encounters. Its dynamic breaching pose creates a natural focal point for ship-to-monster combat on your tabletop.
What printer is recommended for the Leviathan?
A large-format resin printer (Saturn-class or larger) is recommended for 75mm scale. At 32mm, it fits on standard build plates. Multi-part assembly ensures reliable printing at any size.
Played Leviathan at your table? Log in with your Obsidian Tavern account to leave a balance note, a war story, or a file issue — the sharpest reports get the block revised.
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