Siyokoy
Siyokoy — The Encounter
Scaled drowner of the brackish shallows, Philippine merfolk-fiend · a boss your table can run with almost no prep. SRD 5.1-compatible.
Who Is Siyokoy
The siyokoy haunts the brackish boundary where river bleeds into sea, in the mangrove mouths and reef-shadows of the islands. Fishermen speak of it in lowered voices: a scaled man taller than two men, gilled and clawed, its eyes filmed like a drowned thing's. It does not hunger so much as covet the living breath it lacks, and so it drags the warm down into the cold. Nets that come up shredded, a paddler gone between one stroke and the next, a body recovered with the lungs full of silt and the wrists ringed in claw-marks. The old folk leave rice and salt at the tide-line and never swim alone after dusk. To meet a siyokoy in open water is to be already half-drowned, for the deep is its house and you are merely a guest it intends to keep.
Run Siyokoy in Sixty Seconds
- Hold for water. The siyokoy only shines near a body of water — fight it on dry land and it loses Undertow Grip, the drown clock, and most of its threat. Lure or force it ashore if you can.
- Open with Hauling Grasp. Grab the lowest-escape-DC target turn one, drag them under, and start the drowning rules; everyone else now has to peel instead of attack.
- Kill-priority: water-breathers. Anyone with water breathing, freedom of movement, or a way to grant it shuts the whole grapple-and-drown kit down — drop them or it first.
- When bloodied, it dives to deep water and fights from below, baiting the party into the place where it has every advantage.
- Three ways to run it: a lone ambush predator from the reeds; a paired controller herding prey toward a bigger sea-boss; or the warden of a flooded lair where the rising tide is the real enemy.
Siyokoy
Large monstrosity, neutral evil
CR 6 · 2,300 XP · GUIDELINEAmphibious. The siyokoy can breathe air and water.
Undertow Grip. (signature) The siyokoy has advantage on grapple checks against any creature in water, and a creature grappled by it cannot regain hit points until the grapple ends. While in water, the siyokoy can drag a Medium or smaller grappled creature with it when it swims, no extra cost to its movement.
Actions
Multiattack. The siyokoy makes two Claw attacks and one Bite attack. It can replace the Bite with one use of Hauling Grasp.
Claw. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 12 (2d6+4) slashing damage.
Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6+4) piercing damage.
Hauling Grasp. Melee Weapon Attack: +7 to hit, reach 10 ft., one Large or smaller creature. Hit: the target is grappled (escape DC 15). Until the grapple ends, the siyokoy can drag the target underwater, where the target must hold its breath or begin drowning.
Bonus Actions & Reactions
Slick Lunge. Bonus Action. While in or adjacent to water, the siyokoy moves up to half its swim speed without provoking opportunity attacks.
A hulking man-fish of overlapping green scales, fin-crowned skull, and webbed claws, frozen mid-stride as it heaves itself from the surf onto sea-slick stone.
Siyokoy, Bound
Companion · acts on your initiative
Bound · GUIDELINEWater-Sense (signature). Siyokoy has blindsight 30 ft. in water and cannot be surprised by a creature that is in or under the same body of water.
Actions
Constricting Coil. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 10 (2d6+3) bludgeoning damage, and a Medium or smaller target is grappled (escape DC 14).
Reactions
Tow Under. When an ally in water hits a creature with a melee attack, Siyokoy can move that creature up to 10 ft. toward deeper water.
A serpentine companion-spirit of black water, summoned to herd prey into the drowning-dark.
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.
Open from the water so retreat costs an action; Hauling Grasp the squishiest caster and drag them off the bank. If the party clusters on a pier or shore, swim under and pull one in per round. Pair it with a lair hazard (rising tide, slick footing) rather than running it alone.
Lead with Hauling Grasp on whoever has the lowest STR/escape odds and drag them underwater to start the drown clock, then Multiattack anyone who wades in to rescue. Kill-priority is anyone who can breathe water or grant water-breathing — they neutralize its whole kit. Run it with a school of minions or a bigger threat; it is a controller-brute, not a centerpiece.
Open by grappling and submerging the party's anchor while minions screen the shore so no one can free them in time. When bloodied, it dives deep and fights from below, forcing the party to follow into its element. Pair it with a flagship sea-boss or a lair full of currents and drowning hazards — solo it is out-acted by four PCs.
Put Siyokoy 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 Siyokoy?
Its home tier is CR 6 (Tier 2, levels 5-10): AC 15, 119 HP, +7 to hit, save DC 15. Scaled stat lines for Tier 1 (~CR 2) and Tier 3 (~CR 11) are provided so you can drop it into any table without rebuilding it.
Can Siyokoy be a companion or ally?
Not really as a player ally — it is a coveting, drowning predator with neutral evil leanings. The included Eel-Shade, Bound is the on-table companion piece: a water-sensing serpent-spirit that herds prey into deep water for the siyokoy to finish.
How do I make the fight fair on dry land?
On land the siyokoy loses Undertow Grip's water bonus, the drown clock, and its swim speed, dropping it roughly a full tier in threat. Either let the party earn that by forcing it ashore, or compensate by giving it a flooding battlefield, allies, or a higher tier line.
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.
Technical Specifications
32mm, 75mm
STL, Pre-supported STL
Standard or ABS-like resin, 0.05mm layer height
Yes — ready to print, optimized supports included
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